This SwaddleDesigns zzZipMe Sack is perfect when baby is ready to graduate from swaddling. The zzZipMe Sack is a wearable blanket that features a clever 2-way zipper; it opens from the top as well as the bottom so Baby stays snugly warm during diaper changes. EcoFleece is made from 80% GOTS Certified Organic Cotton and 20% Recycled polyester; it"s is plush and fuzzy inside and out, with soft satin-trimmed edges. This zzZipMe Sack has a TOG rating of 2.2 which is appropriate for a sleep environment about 65-70 degrees F, the temperature range that most medical experts recommend for sleep environments.