100% cotton material. Very cute one piece body suit. Looks great and feels great. Metal button brass - Zinc plated. Contains snaps between legs for closure. Onesies are unisex, worn by both girls and boys. An infant bodysuit is a garment designed to be worn by infants much like a t-shirt; they are distinguished from t-shirts by an extension below the waist, with snaps closure over the crotch. The purpose of the opening at the crotch is to facilitate access to the wearer's diaper. Make a great gift. ACU digital camo military style one piece infant suit.