The See-Thru Nipple Boosters can enlarge and stimulate your nipples. Suction and increased blood flow to the nipples increases sensitivity as well as pleasure. Simply place them over the nipples and squeeze the bulb. The nipple bulb will create a vacuum sensation when you release your fingers. After you release the nipple boosters they will stay in place. With the see through chamber you get to see all the action too! Material: TPR