Uniqlo Kiwami (Extra Warm) Heattech Crew Neck T-Shirt Black Unisex Long sleeves, can be worn as underwear, but also as a long T-shirt on its own. I am selling this because I outgrew it after only wearing it a few times. There are no noticeable stains, but it tends to attract a bit of lint. Please only purchase if you understand that this is a used item.