Kaiya Angel baby sleep sacks are made of 100% premium organic cotton that can relax the baby's delicate skin and reduce tension for better sleep. It can be divided into 3 categories: Swaddling, Transitional Sleep Sacks, and Independent Sleep Sacks. We designed baby sleep sacks that will keep every baby feel comfortable all night. Our swaddling sleep sacks are perfect for newborns because they help soothe your infants - parents can wrap babies in the sleep sacks to keep them feel safe. According to the TOG rating, there are 4 ratings as below. The higher TOGs are, the warmer a sleep sack is.