Pigeon Peristaltic Plus Nipple is of flawless shape and size to fit into the sucking fossa of baby. Inner vertical lines fortify the structure of nipples; making it collapse-resistant. Textured surface permits baby to latch on with ease and securely. 100% silicone nipple; super soft and flexible, lets natural and smooth tongue movement. Air Ventilation System (AVS) reduces intake of gas, a potential cause of colic.