New in Bag Kyte Baby Medium Sleep Sack in Coffee Rainbow 1.0 TOG Voted the No. 1 Wearable Blanket by The Bump in 2019, our sleep bag is made of 97% bamboo rayon. The bamboo fabric is breathable and buttery soft to the touch. This sleep bag also features a J-shaped double zipper, which makes it super easy to use. At 1.0 TOG, it provides the ideal warmth all year round.