Certified OEKO-TEX® Standard 100; Hypoallergenic, breathable, wicks moisture; Ultra-soft 95% bamboo viscose, 5% spandex This sleep sac has been absolutely amazing!! So buttery soft, Nicely weighted and so easy to use. The zippers are easy to zip, and zip all the way around which is super perfect for diaper changes and easy wearing. Baby is obsessed with the feeling of the fabric, sleeps so well in that. This size will last you a long time, lots of leg room. We have used this since 12 month until 14 months, and regretted didn't get it sooner. 1.0 TOG sleeping bag keeps baby warm, snuggly.