Enhance your assets with this sexy nipple erector kit. This set of nipple pumps comes with two manual pumps; one with a smaller opening to start with, and one with a larger opening to make your nipples even larger, if desired. Simply slip on one of the O-rings from the several sizes included over the pump tip beforehand. Once the desired perk is achieved, slip the O-ring off the pump and around your nipple to keep the effect and keep your nipples (and your lover!) firm and ready for play. The 4 o-rings come in varying sizes. The thickness of all rings is .75in. The widths are: XL = .6″ L = .525″ M = .440″ S = .375″