SwaddleDesigns zzZipMe Sack is perfect when baby is ready to graduate from swaddling. Made from the same preshrunk cotton flannel as our ultimate receiving blankets with soft satin trimmed edges. The zzZipMe Sack (wearable blanket) also features a clever 2 way zipper, opens from the bottom as well as the top. The zipper zips down from the top making it easy to place baby into sack and also zips up from the bottom keeping baby snugly warm during diaper changes. This zzZipMe Sack has a TOG rating of 0.7 which is appropriate for temperatures of 72 78 degrees Fahrenheit. Please note most medical experts recommend a sleep environment of 65 70 degrees Fahrenheit. SwaddleDesigns zzZipMe Sack with exclusive zipper is a patent pending design. 100% cotton flannel, machine washable and proudly made in the USA.