My husband used this as an inner layer when mountain climbing, but he hasn't had any climbing plans in the last few years, so I'm listing it at his request. MOUNTAIN EQUIPMENT - Size: Unknown (likely M size) - Color: Gray ※ As shown in photo 7, the size notation on the collar is missing, but according to my husband, it's equivalent to a men's M size. ※ It will be shipped in an IKEA zip-lock bag via regular mail.