Uniqlo long-sleeved undershirt, pink, size 140. I thought it was Heattech, but there's no Heattech or Airism mark on the tag, so it might just be a regular undershirt ^^; I used it without a problem even in the dead of winter. It's not 100% cotton, but a blend with polyurethane. I mostly wore other patterned ones, so I think this one can still be used, but if you're particular about details or looking for something brand new, please refrain from purchasing.