New bamboo sleep sack. 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. TOG 0.5 Shell: 95% Viscose Bamboo 5 % Spandex Lining 95% Viscose Bamboo  5% Spandex TOG 1.0 Shell: 95% Viscose Bamboo 5 % Spandex Lining 95% Viscose Bamboo  5% Spandex Filling 100% Polyester  Wear Snug fitting not flame resistant  Care: Wash inside out, machine wash cold water ,gentle cycle DO NOT BLEACH Flat lay to dry or tumble dry on low heat  cool iron if needed