Nukeproof Merino Long Sleeve 1/4 Zipper Baselayer

The great thing about Nukeproof's Merino Long Sleeve 1/4 Zipper Baselayer is its ability to perform across a wide range of temperatures and conditions. When it's cold it's a great insulator, and yet it's naturally breathable and odor resistant too; moisture quickly evaporates when the fibers can’t hold any more, helping you maintain your temperature and avoid overheating when riding hard. 

Nukeproof give the base high neck to seal in warmth, and it can be easily unzipped if you get too hot.  A raglan sleeve construction with flatlock seams give you extra comfort and you'll find thumbholes at the cuff to keep out the elements. With a looser mountain bike style fit you'll also love the freedom of movement it gives under your MTB kit.