Fleece, made in USA from Japanese polyester and rayon. Booties that are marketed as fitting a 0-6 month old, but in reality are appropriate for your average 12-18 month old. My son is in the 99th percentile for height at 12 months, and I just tried these on him and they fit. They were tried on as they were a gift, but didn’t fit at the time, and we just have no use for them… passing them on. One has a little button on the back, and one has a little loop.