SSK Baseball PROEDGE Underwear Contact Cold Feeling Low Neck Crew Neck Round Neck Long Sleeve Fit Undershirt Size: S (Slim fit) Color: Navy I bought this for my elementary school (upper grades) son. It was a men's S size, but it was quite slim and tight, and he only wore it twice. It's also too small for my 165cm, 50kg middle school son. I think it would fit a slim elementary school student. Used, with wrinkles. Please understand before purchasing.