The Nipple Bulb is a gentle little suction device for enhancing and raising your nipples. Just apply to the nipple and squeeze for light, comfortable suction. To use the erection O rings, slip on the vacuum tube before suction begins. Then, slide off tube onto the erect nipple. It has a two inch suction bulb for gentle, pleasing pleasure, a clear tapered vacuum tube for comfort and comes complete with 4 nipple erection rings. Vacuum bulb with 4 nipple erection rings ABS (nozzle) PVC (bulb, rings) .4”/1 cm (tip diameter)