Having your boy stay warm is probably as crucial to your ski day as it is for his. Luckily the Helly Hansen Boys' Warm Set 2 ensures a season of comfort and bliss at least as far as long underwear is concerned. The Warm Set features Helly Hansen's HH Warm technology which is a pairing of merino wool for comfort and warmth with Lifa Stay Dry technology which ensures that his skin stays dry all day a crucial element in the battle to stay warm. In order to maintain comfort over a long day Helly Hansen also used flatlock stitching.