Aclima WarmWool Mockneck is a long-sleeved shirt with a low collar that helps retain warmth around the neck. A snug fit, it works perfectly closest to the body on cold days. Zipper at the neck for best temperature regulation. WarmWool is a knitted material and thus elastic and flexible. The fabric is made of 100% merino wool, with a weight of 200gsm. The fibres in WarmWool are 20.5 microns, the material is soft and comfortable against the skin. WarmWool is suitable as a next-to-skin layer or second layer when it gets really cold.