Haglöfs L.I.M. ZT II Men’s Air Bottoms review: flighty light undies for tackling trails, crags and summits

First impressions

As with everything else in the new L.I.M. ZT II range from swanky Swedish outdoor brand Haglöfs, the Men’s Air Bottoms come with a hefty price tag that feels as though it weighs more than the garment itself. Can you justify such an outlay for a pair of boxer briefs? Well, that depends on how much value you place on being comfortable and staying cool when you’re at the crag, on the trail or making your way up a mountain.

While they look and feel very lightweight, these underpants (well, their designers and marketers) talk a big technical game. Over the last few months, I put my backside on the line to test the Men’s Air undies out, and get to the bottom of whether all these claims are legit, or whether the brand is talking a load of Swedish meatballs.

Design and materials

The Air Bottoms can be used as running underwear, used in conjunction with leggings or trail running short that don’t come with an integrated liner, or worn beneath hiking shorts and pants. But, if you consider that good base layers in general don’t receive the credit they deserve when it comes to the adventure wardrobe (and they really don’t), then underwear gets a proper bum deal.

In much the same way that hikers obsess about boots and shoes, and then don’t spend enough time pairing them with decent socks, people will pore over the pros and cons of climbing and hiking pants for hours, and then wear any old undies beneath them. Wiser hill walkers and mountain moochers will tell you that comfort starts at the bottom of the layering system, so the very first thing you put on when you get up on the morning of an adventure is crucially important.

Made with Polartec Delta fabric, these undies aim to keep the wearer cool and allow the body to breathe during dynamic activity. The material mix is an even split between recycled polyester (which is tough and long lasting) and lyocell, a substance sourced from plants which is relatively ecofriendly, comfortable to wear next to the skin, and can deal with the build-up of bacteria that leads to bad odors (obviously, you do still need to launder them regularly… it can’t do all the heavy lifting). There is also a pinch of elastane in the ingredients, which gives the garment dynamic stretch, keeps the underpants in place and helps maintain their shape.

Arguably the most important trick the Polartec Delta fabric brings to the pants party is the ability to wick moisture (sweat) away from the body with its hydrophobic yarns, before encouraging it to evaporate with its hydrophilic yarns. This clever process keeps the wearer cool, and dry, and reduces the risk of such adventure-ruining horrors as nether-region chafing.

However, the design and material mix also means they are supportive where it counts, and there is plenty of stretch in the fabric, so your range of movement is never impeded. Cleverly, the elasticated waist band, which keeps the underpants in place, perforated with hundreds of small holes, to make even that element of the garment more breathable and less sweaty.

On the trails and in the hills

I have been wearing the L.I.M. ZT II Men’s Air Bottoms for all kinds of outdoor pursuits over the last few months, from running around trails (beneath shorts, I hasten to add), to using as an underlayer for hiking, biking, scrambling and climbing. My review, in a nutshell, is that they’re excellent undies for any dynamic adventure activity in which you’re likely to break a sweat – which has been especially good during this multi-heatwave summer. They deal with sweat brilliantly, and never get clingy and uncomfortable.

Running shorts often come with an integrated liner, but many – such as the Adidas Terrex Multi Trail Running Shorts and the Rab Talus – don’t, which means you have to decide whether to go commando or wear undies while you tackle the trails. If you do choose to go with an underlayer, don’t go with a thick pair of cotton boxers or briefs, as these will quickly become sweaty and nasty, leading to discomfort and potentially horrible chafing issues. I found the L.I.M. ZT II Men’s Air Bottoms brilliant for running, because they’re supportive, very breathable and the Polartec Delta fabric very effectively wicks moisture away from your body.

Whilst hiking, climbing and messing about on mountains – where I have been lucky enough to pair the them with other items in Haglöfs’ new L.I.M. ZT II range, including the excellent Flex Trousers – the L.I.M. ZT II Air Bottoms have proved themselves as the perfect underpants. They permit a really good range of movement, so you can scramble over boulders, stiles and over obstacles, and reach out for footholds on the crag. And, as above, they keep you cool where it counts and reduce sweating and rule out any chafing problems by wicking moisture away.

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