Nipple Boosters can enlarge and stimulate your nipples. Suction and increased blood flow to the nipples increases sensitivity and pleasure. Simply place them over the nipples and squeeze the bulb to create a vacuum sensation when you release your fingers. After you release the nipple boosters they stay in place. Measures 2.63 in. long 1.1 in. opening inner diameter 1.7 in. bulb diameter.