Introducing the Bamboo Sleep Sack Wearable Blanket, a luxurious and eco-friendly solution for your baby's sleep needs. With its breathable bamboo fabric your little one will be comfortable and safe all night long. Give them the best sleep possible with this must-have wearable blanket. Sleep Sack Length : 0-6 Month 27" 6-18 Month 37" 18-36 Month 40" Bamboo is temperature-regulating and while we’re pretty confident it’s the softest fabric you’ll ever feel, it’s also ultra-stretchy. TOG (or Thermal Overall Grade) is a rating system that measures warmth and calculates how quickly a fabric uses heat. We recommend a heavier TOG during cooler months and a lighter one during warmer months.