During the first year, after baby has transitioned from swaddling, experts recommend a wearable blanket for sleep. The eco fleece zzZipMe Sack is wonderfully soft, high-quality, and features a 2-way zipper that makes our sleep sack easy to use. TOG 1.5. Easy to place baby in the sack when unzipped from the top and keeps baby warm during diaper changes when you zip up from the bottom. Award winning design features eco fleece fabric (80% Certified Organic Cotton and 20% Recycled Polyester) with silky satin trim.