Size medium 13-19 los Unisex gender neutral 2 in 1 arms up swaddle and arms out sleep sack 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.