The TRANSITIONAL SWADDLE SACK allows baby to SELF-SOOTHE and promotes BETTER SLEEP and SAFER SLEEP; Perfect for babies who prefer to sleep with ARMS UP babies who are starting to rollover and babies able to break out of a traditional swaddle | LITTLE SLEEVES with BIG PURPOSE; The 1/2-length uniquely-shaped sleeves with mitten cuffs closed provide partial suppression of Startle Reflex to help baby SLEEP BETTER and if baby rolls onto tummy baby can push up to reposition head to access air | EASIEST way to wean from traditional swaddle; TSS is not a tight swaddle nor a loose sack; May seem small but SNUG FIT around tummy and shorter sack support legs in flexed position help baby feel secure to SLEEP BETTER; Can adjust neck size with zipper | FOLDOVER MITTEN CUFFS MAY BE WORN OPEN OR CLOSED; Caregiver can open one or both cuffs so baby can SELF-SOOTHE or close the cuffs to PROTECT BABY FROM FACIAL SCRATCHES and provide partial suppression of startle reflex | HELPFUL 2-way zipper for easy diaper changes. Soft stretchy cotton knit. SNUG fitting design supports baby in natural flexed position. Small 6-14 lbs 0-3 Mo; Medium 14-21 lbs 3-6 Mo; Large 21-24 lbs 6-9 Mo; US Patent D833613 and EU China Patents | Target gender: unisex