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Definition [Mens] waterproof mountaineering shell

Definition [Mens] waterproof jacket Reef blue


  • Reef - Definition [Mens] waterproof jacket Reef blue
  • Black - Definition [Mens] waterproof jacket black
  • Blaze - Definition [Mens] waterproof jacket Rocket orange

Waterproof mountaineering jacket for the harshest of conditions: impenetrable storm protection, whatever the mountains throw at you

SALE: £189.99 Was: £229.99

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  • Full Description
  • Features At A Glance
  • Care & Environmental Advice
  • Size Guide
  • Customer Reviews
  • Kudos

Under siege again. Shards of wind-lashed ice and volleys of rain pummel your defences, the jagged rockface above slicing through any remaining resolve. ‘Where are those pristine conditions promised by the long-range forecast?’ Fortifications still standing, you push on... 

A fortress of a jacket, the Definition has been designed to safely encase you from the wettest, windiest, and wildest of mountain weather. Fully featured and tough as old boots, the Definition is the ideal jacket for Scottish winter epics, committed alpine climbing and year-round Munro bagging.  

Highly waterproof (30K HH) and breathable (20K MVTR), the Definition will keep you safe and dry, even in savage highland storms. We’ve used a 3-layer construction, providing long-lasting performance and protection from exposure. Whether scrabbling up chimneys or scraping along traverses, the durable nylon outer stands up to the rough abuse of mountain use, and a strong nylon backer protects the PU/PTFE waterproof membrane.   

Designed to sit over multiple layers, the Definition is cut with pre-shaped arms to avoid riding up and exposing your back or tum when you’re reaching up for holds or swinging ice-axes. A large hood is sized to comfortably fit over a climbing helmet, deflecting spindrift from engulfing your core, and the wired peak and three elastic adjusters allow you to really batten down the hatches when the weather rolls in. A two-way YKK Vislon Aquaguard main zip (complete with internal storm-flap) accommodates harnesses, completing the mountaineering-ready feature set. 

Map-sized main pockets have been designed to sit clear of your rucksack straps, hip-belt or climbing harness, as have the innovative vents. The inverted vent-zips are easier to open and close when overheating than traditional pit-zips, giving you easy access your mid layer pockets too. All external zips use YKK Aquagard water-resistant zips and an internal and external chest pocket add secure storage options. Catch-proof hem adjusters are neatly concealed within the main pockets, and gusseted cuffs fit easily under or over gloves, with anti-snag Velcro adjusters. 


'The Definition is arguably as good or better than some jackets costing twice as much. The cut is sleek and efficient, components are top-notch... the unbranded fabric works well and feels reassuringly tough. The effective helmet-compatible hood means you can use it for anything from full-on mountaineering to general hill-walking' - Outdoors Magic 

Product Insight
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Key features
  • Reliable 3 layer construction is highly waterproof and breathable (30K HH and 20K MVTR) keeping you dry in the wettest of conditions
  • 40 x 90 denier nylon outer fabric is exceptionally hardwearing for rough mountain use
  • Helmet-compatible hood is fully adjustable (side and rear adjusters) with a stiffened and wire peaked hood to protect the face
  • Water resistant Aquaguard Vislon main zip is protected by an internal storm flap and is two-way to accommodate harnesses
  • Cut to fit easily over multiple layers with pre-shaped arms to avoid riding up when reaching for holds
  • Map-sized main pockets and an external chest pocket with water resistant YKK Aquaguard zips, plus an internal chest pocket
  • Side vents with inverted zips are easy to open, give access to mid layer pockets, and are placed to sit above hip belts and harnesses, as are the main pockets
  • Gusseted cuffs fit easily over or under gloves and are secured with anti-snag Velcro adjusters
  • Hem adjusters are placed within the main pockets to avoid catching
  • 3 Year Alpine Bond
Vital stats

145 gsm 3 layer fabric
Face: 40 D x 90 D Nylon
Backer: 20 D Nylon tricot
Bi-component PU/PTFE membrane


Hydrostatic head: 30,000 mm
Moisture Vapour Transfer Rate: 20,000 g/sqm/24hrs


M: 515 g

Origin: China

Environmental Considerations

We treat all our waterproofs with PFOA-free DWRs, cutting out some pretty nasty chemicals. Unlike our insulation and sleeping bag ranges, our waterproofs are not yet PFC-free. We’re still looking for a PFC-free DWR that’ll provide the same long-lasting performance for waterproofs, but we are working on it!

We make gear you’ll love for longer: gear that lasts; gear you’ll use, repair, re-use and pass onto someone else when you’ve finished with it. That’s why all our products have a three-year Alpine Bond warranty as minimum. We’ve always thought that the most environmentally friendly product we can make is the one that gets used the most and lasts the longest. So that’s what we do - it’s pretty simple really.

Product Care Information

The better you look after this jacket, the better (and longer) it’ll look after you. Well, when we say ‘look after you’... it’s not gonna make you cups of tea or bring you breakfast in bed, but it will keep you nice n’ dry. And the good news is: it’s dead easy to do.

1) After you’ve finished going nice places and doing good things, treat your jacket to a wash at 30°C with either a dedicated Tech Wash (like Grangers and Nikwax) or pure soap. This keeps your jacket breathable by stopping the Durable Water Repellent (DWR) coating from getting clogged up with dirt and skin oils. No one likes a sweaty, clammy jacket.

2) If it’s stopped beading (rain soaking in rather than forming droplets), you can reactivate the factory-applied DWR by sticking it in the tumble drier on a low setting or applying a cool iron to it (under a tea towel).

3) To keep your jacket beading, you’ll probably need to top up the DWR once or twice a year using a Grangers or Nikwax re-proofer. You can find out more about why this is important here.

If you’re still a bit unsure about washing your jacket, you can also take it/send it to our Ambleside store’s waterproof washing service and we’ll sort it all out for you.

Size chart Waterproof Jackets Mens
Men's waterproof jacket sizing chart
Chest (inches) 37" 40" 43" 46" 49"
Waist (inches) 30" 32" 34" 36" 38"
This size chart indicates the body measurements our garments are designed to fit. Measure yourself as described below, and use the size chart to find your size.
Chest: measure around your chest at the widest part. The tape measure should pass under your arms, and be level from front to back.
Waist: measure around your waist at the narrowest part.
Hips: standing with your feet together, measure around your hips at the widest part.
What You Say: Customer Reviews and Comments

18 Reviews


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Christian Lee
Great for when the heavens open

Used my definition jacket during a wet ascent of Helvellyn. Breathes well for a full on waterproof and certainly able to cut the wind chill easily absorbing 50+ mph gusts. The definition was not penetrated and I remained dry throughout.

Trust in Alpkit...

I'm currently doing a long distance bike trip / hiking around the globe and my rain jacket broke. Since my experience with Alpkit products have been very good so far I decided to buy the Definition. So far I'm very content with the product. The cut is really good and also suitable for biking. I'll see what it will bring in the long run...


I’ve had this for 2 years now and it’s still good as new despite being out on numerous adventures. Waterproofing / breathability is excellent, and the fit is great. Top tip from the alpkit website that light heat can reactivate the DWR when reproofing. Thanks guys.

The first of many...

I bought this coat to replace my ailing 10 year old ME Morpheus and it's more than a worthy replacement. I've had it for 3 months now and it hasn't let a drop of water through. It's a nice snug fit and it doesn't ride up my back when moving about. It's not branded goretex but it looks and feels military grade, the taped seams are spot on and it's one heavy duty hardshell.
I'd driven past the Hathersage store dozens of times before finally stopping to go in. Helpful friendly staff with a nice easy going approach and bang on products to boot.
My wife calls me a 'coat tart' so as the title says, this may be the first of many Alpkit adventures...


This jacket is amazing. I am yet to use it in the mountains, but after several canoeing and camping trips in bad weather it hasn't let me down. The cuffs are amazing, miles ahead of any other jacket I have used. Water just doesn't get in and yet I can easily get a pair of gloves tucked in underneath. The whole cut, in general, is brilliant, not at all restricting and yet with enough room for layering. In fact, the whole jacket is just brilliant and from a really nice company, bought this from the Ambleside store and the staff were really nice. Top notch Jacket!

Craig O
Excellent Hard Shell

Just come back from a week of walking in Snowdonia, it rained all day every day! This jacket kept me dry throughout and never wetter out. It also survived being caught on barbed wire with no damage to show for it!

A superbly designed jacket

The tailored fit allows easy movement and just the right amount of room for layering without feeling baggy or flapping in the wind, the sleeve length is perfect. It doesn't ride up at full stretch and the hood fits fine with or without a helmet. The fabric feels bomb proof, and has kept me totally dry in torrential downpours and hours of drizzle. It has decent breathability to boot. There are lots of ergonomic design features. I trust this jacket to perform well and to keep on performing in UK hills and mountains when other significantly more costly jackets have disappointed me.


I've used this jacket in anger about 20 times in the last couple of months. First for a very wet Scottish winter climbing trip, and then for a scalding ski trip in the French alps. I stayed completely dry through torrential rain, and pleasantly cool in the sun.

The fit is fantastic, more athletically cut than the ME Lahotse jacket (that the Definition can easily compare to). Comfortable for all day mountain slogs, and warm enough for standing around in car parks in the peak district.

My only criticism would be the pit zips. The placement makes them easier to use than the traditional underarm zips. However, because they are not over your hot armpits they didn't feel as effective as those on other jackets.


Used this jacket in Chamonix skiing this week and it was fantastic. Completely waterproof and windproof and a great fit. Way better than jackets for twice the price from the famous skiing brands.

Just awesome

Just used this jacket for a week of winter mountaineering in Scotland, including the wrath of storm Doris. The jacket was outstanding! Excellent breathablity and totally wind proof in what was gusting up to 70mph at times. Love it!

Matt S
Great Jacket!

I have used this jacket a few times for skiing since I bought it and I love it! It totally blocks out the wind and is still very breathable. Looking forward to taking it out the Scottish highlands for a bit of mountaineering and climbing in a couple of weeks time. Great job guys! grin

Proper Job

A good waterproof is an expensive essential for any mountain walker with prices now eye watering for the best kit. But yet again Alpkit have bucked that trend with a well thought through jacket at a sensible price. At 500g it saves 250g off the jacket it replaces and yet is sturdy and windproof (and well tested in the lakes this December!). At this level good waterproofing and breath-ability is a given as are the layout of pockets. I'm 6'2" and wear an XL. If I wanted a shaped fit I'd probably go for a L but the size up works well over fleeces or jackets. I have a Kabatic to give insulation and the colour co-ordinated combination work brilliantly. The location of pit zips is interesting. Alpkit have moved them lower on the jacket so you dont have to faff under your pack shoulder straps. This means that they no longer ventilate your hot underarm, more the back. We'll see if works in the longer term but is a good example of how this company dont just follow fashion, but are willing to think through technical problems with a fresh eye. At £210, it's a bargain and well worthy of five stars.

Great jacket but....

Performs well. The one gripe is the way the hood cords are tightened. The push buttons just do not work properly and the cords slip. One has never worked properly at all but I didn’t wear the jacket for a while after I got it so it was a bit late to say. Normal cord holders would be better. Hence 4 stars.

Definition Waterproof

I bought the jacket over a year ago after my berghaus paclite jacket finally gave up after 10 years. So far its done 2 winter seasons in the caingorms going mixed climbing and numerous scout weekends and dog walks. It is still 100% waterproof and the fit is really good with space underneath for big fleeces to keep warm. I'm 6'2" so bought a size large and the sleeves are nice and long as is the back length so it doesn't ride up. The material seems to be very tough and has survived ice axe points going in the wrong direction.

It would get 5 stars but I find the pockets go too far down the jacket and so when I put my hipbelt on I need to shuffle everything in them up so they don't get squished. The side vents are a little hard to operate but they don't get covered by your rucksack straps so that evens it out.


Great jacket. But doesn't quite compete against the Mountain Equipment Changabang. Zip in/out snow skirt and a shoulder zip pocket would make it perfect.

david mccormick
had it now for a year

Really good simple design, the two main pockets arte useful but the chest pockets (inside and out) are virtually useless as they are too small to fit anything more than a compass. Could have easily extended to accommodate larger phones etc. Not enju=oyed the venting zips, just too much rain water access when its wet - pit zips stay much drier while cooling hot pits. Other competitors are not significantly more expensive so maybe not a compromise I would make in the future.

Great jacket for price but not quite up there yet

I just bought this jacket as been meaning to replace my old ME Changabang Pro Shell jacket (about 14 years old!). And i saw in a review is was a good contender. The price attracted me albeit i have always worn Goretex in the past so this will be my first daring breakaway. not used in Anger (clearly as it's a Heatwave ) but i would say it's a heavier fabric than my old jacket and a lot heavier than the new Goretex Pro versions. and no ski pass pocket is a mistake, a zip out snow curtain would be nice too. That being said, some good features, looks great so at £189 (sale price) i'll give it a go.

Not the worst but certainly not the best

I read all the good review and really had my hopes up for this jacket. So I ordered it and wore it for the first time on a week's hike on the Skye Trail. This review comes after only 7 days of pretty much consecutive use, but I don't see how any further use could change my review (towards the positive at least).
- Sizing and fit are spot on. Loose enough to go over a light down jacket, but still not too baggy when there's only a base layer underneath. And the arm-movement is one of the best.
- Pockets are where they should and their zippers work fine.
- The hood adjustments do just what they should.
- The DWR is gone for good in a matter of hours. Seriously, the first rainy day and about two hours into the rain, and no more water beading off the jacket: it just sinks right in. And no, it doesn't recover after drying, but I'm yet to try other tricks (like ironing or tumble drying).
- Eventually, the rain comes through. Yes, this means that at least my jacket is not fully waterproof. It could be okay for letting your dog out in a rain or similar activities. But when spending 7 consecutive days out in the wild, and even your base layer gets soaking wet after 5-6 hours in the rain with this jacket, things get serious if not dangerous.
- The shell doesn't breath too well. While hiking with a backpack or doing something else physical, it's pretty easy to get a lot of sweat inside the jacket.
- The vents are positioned so, that in a rain it rains right inside. Whereas, an underarm zipper (even if harder to operate) could also be used in a rain. That is when the ventilation is needed the most.
- The seam tapes start to wear off in a matter of days (see the photo)

TL;DR: Would never recommend using this jacket in a situation, where staying dry is important. It just doesn't do what is promised. And if getting wet is okay, a cheaper jacket can probably do the job.

What They Say: Kudos - Product Reviews from independent magazines and websites

OM Reviews 2016/17 New Product

immediately impressive

Outdoors Magic

Outdoors Magic December 2016 -

UKC reviews Definition

Definition screams good design


ukclimbing.com January 2017 - Dave Saunders

Outdoors Magic Definition Review

Alpkit’s full-on mountaineering shell, the Definition is reassuringly burly but properly refined – think James Bond reincarnated as a waterproof jacket. And the price is fantastic.


Outdoors Magic February 2017 - Jon Doran

Best Value

The Alpkit Definition wins ‘Best Value’ in Trail’s Waterproof Jacket group test.

Ideal jacket if you want practical features at a good price

Graham Thompson

Trail October 2019 - Graham Thompson, Anna Humphries, Tim Butcher

Trail Magazine Approved

Trail Magazine: Definition & Balance Waterproofs

Trail Magazine October 2017 - Trail Magazine

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