HALO SleepSack Swaddle. This product is a wearable blanket designed to replace loose blankets in a crib for a safer sleep environment for infants. It is a 3-way adjustable swaddle that allows for swaddling with arms in, hands-to-face, or with one or both arms out. The swaddle is made of micro-fleece, which is a soft, plush, 100% polyester fabric. The size shown is a small, intended for babies who are 3 to 6 months old and weigh between 13 and 18 pounds. It features an inverted zipper for easy diaper changes.