Running in technical baselayer with Polygiene anti odour technology

How to Choose an Base Layer for hillwalking

By Mark Roberts

Too many tees. Too, too many tees. With so many ‘technical tees’ out there, each claiming to be more technically advanced than the next, it's tough to know which is right for your outdoor needs.

Phrases like ‘moisture-managing’, ‘temperature-regulating’ and ‘ultra-wicking’ can quickly make you feel like you’re buying clothing to survive on the International Space Station, rather than choosing clothing to keep you cool and dry out in the great outdoors!

We like to keep our ranges small, but perfectly formed. Each of our base layer tops have been conceived by the Design Team to do a very specific job - and to be worn for as many different activities as possible so you don’t have to buy millions of different ones!

Here’s a quick run-down of the range to help you sort your Keplers from your Koulins and your Picus from your Vaypers!


  1. A Quick Comparison
  2. The Koulin Range
  3. The Vayper Range
  4. The Kepler Range
  5. The Picu Tee

A Quick Alpkit Base Layer Comparison

Koulin Vayper Kepler Picu
Fit Slim Tight Slim Slim
Weight - Short Sleeve
(Men's M / Women's 10)
140g / 90g 89g / 68g 160g / 124g 145g / 95g
Main Fabric
100% recycled polyester, 150gsm 100% recycled polyester, 95gsm 100% mulesing-free merino, 160-200gsm, 17.5 microns Drirelease Eco - 85% recycled polyester, 15% organic cotton, 164gsm
Best For
Anything and everything High-intensity activities Feeling extra comfortable Bike tours, treks and coffee stops

The Koulin Range

Our do-it-all base layer tops for wearing alone or as part of a layering system. Made from wicking polyester with mesh panels for increased breathability under layers.

What makes it special?

It’s incredibly versatile. The recycled polyester fabric is durable under rucksack straps or for scraping over over gritstone and gabbro. Plus mesh panels under your armpits increase its breathability in a key area (pe-ew!) when wearing under layers. And there’s a small stash pocket for your house or car key too.

What’s it good for?

Anything and everything: hiking, climbing, running, biking. With short and long-sleeved, round-neck and zipped necks options, we’ve tried to cater for everyone’s requirements.

Is it sustainably made?

As well as making these base layers with 100% recycled materials, we’ve used Polygiene® anti-odour treatment. This increases the number of times you can wear your tee before needing to wash it, making your tee last long and reducing its footprint over time.

The Vayper Range

A true next-to-skin base layer made from ultralight recycled polyester and treated with Polygiene® for better odour-resistance. Designed to move sweat away as quickly as possible to keep you cool and dry whilst working hard.

What makes it special?

As well as fitting neatly under other layers, the Vayper’s tight, athletic cut helps it to draw sweat away from the skin quicker and the ultrafine material is incredibly fast-drying. It will also trap a thin layer of warm air next to the skin when worn under other layers.

What’s it good for?

Wearing under other layers for a range of high-intensity activities. It’s close-fitting enough to be worn under fleeces for hillwalking and climbing or even under bike jerseys for cycling. Because it’s so fast drying, it also makes a great stand-alone tee for running, or hiking in really hot weather.

Is it sustainably made?

We’ve used a fabric made from 100% post-consumer recycled polyester, reducing our dependence on virgin polyester, and the Vayper is also Polygiene® treated to reduce washing.

The Kepler Range

A merino wool tops use 100% ultrafine 17.5 micron merino wool fibres: extremely soft on the skin, naturally breathable and odour-resistant with a fantastic warmth-to-weight ratio.

What makes it special?

The ultrafine merino wool fibres we use are much softer next-to-the skin, dry quicker and have a higher warmth-to-weight ratio than heavier fibres. As well as being naturally pong-proof and breathable (it transports sweat vapour through its fibres), wool has some very clever properties which keep you cool in the heat and warm in the cold.

What’s it good for?

Keeping you comfortable, dry and at the perfect temperature. It’s not as fast-drying as our other base layers, so is less suited to high intensity activity and hot conditions, but it can’t be beaten for comfort in all other situations. The ultrafine fibres will trap lots of warmth in cold weather and wool’s incredible odour resistance makes the Kepler perfect for multi-day trips.

Is it sustainably made?

We only use merino wool from non-mulesing sources. Mulesing is a cruel and unnecessary practice used by some farms to reduce labour costs and increase profits. Wool is a completely natural and sustainable material and its natural odour-resistance means it requires very little washing, (usually a quick air on the line will do), reducing its footprint.

The Picu Tee

A fast drying and wicking poly-cotton tee designed to feel as comfortable next to the skin as a cotton t-shirt.

What makes it special?

The blend of organic cotton and drirelease® branded polyester results in a really soft-feel tee that wicks and dries almost as quickly as polyester base layer and around 4x faster than pure cotton.

What’s it good for?

Seamlessly moving from social settings to activities in the great outdoors. Any situation where you want the performance of an outdoor tee but don’t want to look like you’re dressed head-to-toe in outdoor gear - the Picu makes a great tee for travelling in hot climates.

Is it sustainably made?

The Picu uses Drirelease Eco fabric made from organic cotton and 100% recycled polyester.

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