Size Medium (13-18.5 lbs) Fit & style •Gentler way to help your baby transition from swaddling to arms-free sleep with patented zip-off wings. •Converts to a snug sleeping bag, maintaining the secure feeling of being swaddled. •Twin zipper for easy diaper changes. Easy Care: machine wash on gentle, tumble dry on low. 1.0 TOG fabric is ideal for moderate room temperatures between 68°F and 75°F •Certified 'hip-healthy' by the International Hip Dysplasia Institute allows recommended flexion for hips & legs. Comment for questions.