Double layer 100% organic cotton - This Baby Sleeping Bag is made of double layer premium organic cotton with a TOG rating of 1.0, which is most suitable for moderate seasons or climates, can help your baby get a peaceful, long sleep year-round - being not too hot or cold. Our sleeping sack can be layered with warmer baby sleepwear when used for cooler temperatures. The organic cotton interlock minimizes the risk of overheating and keeps your baby warm and comfortable. | No struggling with those midnight changes - Our sleep sacks feature high quality durable 2-way zippers, which can unzip from the bottom for easy diaper changes. Also, no struggling to connect the zipper at baby's chin, as 2-way zippers unzip from the top and make it very convenient to use. | Your child's safety comes first - No more worries about loose blankets in the crib that can get twisted and tangled easily, and pose the risk of covering baby’s face. Our wearable blankets were carefully designed to provide a safe and comfortable sleeping environment for your baby. Worry free safety tab protects baby's neck and chin, and ensures a secure closure. The bottom zipper cover deters baby's hands from unzipping. | Generously sized and roomy - Our sleepbags are generously sized to fit over sleepwear and carefully designed so baby's leg can move freely to ensure proper hip development. | Small size sleep sacks are suitable for babies from 0-6 months, 10-18 lbs, 23-26 in. Medium size sleep sacks fit babies from 6-12 months, 16-24 lbs, 26-30 in. Large size sleep sacks are suitable for babies from 12-18 months, 22-28 lbs, 30-35 in. X-Large sleep sacks fit babies from 18-24 months, 26-36 lbs, 35-40 in.