Gently used, genuine SNOO Sleep Sack in navy blue celestial print. Size large (18-26 lbs). Also including grey celestial print fitted sheet for SNOO mattress. SNOO Sleep Sack is the ultra-soft, ultra-easy swaddle sack that helps babies be happier and sleep longer—and it’s the only sleep sack that should be used with SNOO! SNOO Sack has special wings that slip onto SNOO’s clips to secure babies on their backs and prevent risky rolling. 100% organic cotton.