This is a Smartwool PhD half-zip. Made of 56% wool and 44% polyester. The mesh under the arms and the half-zip make it easy to regulate body temperature. It worked well worn alone or layered with a Millet Drynamic base layer. It has thumbholes. Regarding the condition, there is some pilling in places due to the merino wool. The fabric still has good structure, and there are no holes or tears, so it can still be worn for a long time. The size is S, but I am 175cm tall and weigh 65kg (for reference, I wear L in Montbell and M in Patagonia), and it fit perfectly over a base layer. Please purchase only if you understand that this is a used item.