Master Series Pyramids Nipple Bulbs O Ring. Nipple Amplifier Enlargement Bulbs with O Rings. The Pyramid Nipple Amplifier Bulbs are an erotic method to have larger, more erect nipples. This enlarger system has four graduated O rings to put within the nipples to ensure that they're standing around attention! Simply slip the preferred size ring within the open finish from the pump just before use, fit the glass pump within the nipple, and squeeze before you achieve your ideal size. Then slide the stretchy rubber ring lower over your engorged nipple, until it reaches the bottom. Two different sized pumps are incorporated, for any custom made on any size. Measurements: pumps are 2.63 inches lengthy, Large Pump opening has .53 inch inner diameter, Small Pump opening has .35 inch inner diameter, O-Rings vary from .33 to .54 inch inner diameter. Materials rubber, glass. Color: Black. Note includes two pumps and eight rings