I believe these are Uniqlo Heattech Waist Warm Short Pants, also known as belly warmer pants. This is a set of 3: 1 black and 2 wine red. Size is L. I bought these a few years ago, but only wore them a few times and they've been stored in the closet since. There is some pilling, but otherwise they are in good condition. I don't think I'll wear them anymore, so I'd like to pass them on to someone who will use them.