Personalized Bike Bum Newborn Layette. Bike bum text with a heart dotting the letter i in the word bike is a fun gift design for bicyclists at birthdays and holidays. 100% combed ringspun cotton 5.8 ounce 1×1 baby rib sleeper. 3/8" flatlock binding at envelope neck and cuffs. Back sleeve flap to protect hands. Elastic opening at bottom. Infant: 0-3 Months