With proper use you can enlarge and stimulate your nipples using our high tech vacuum pump. The pair of cylinders is crafted from industrial grade clear acrylic. Uses the same airlock release system as in our penis pumps. A dual "T" connecter is recommend to enlarge both nipples evenly and to insure constant pressure. Enjoy watching your nipples grow with proper use. Enhance sensitivity of the nipples. Can be used to create great stimulation or punishment with higher pressure levels. We offer two sizes. The beginner size cylinder will make the nipples more elongated after suctioning. The advanced cylinder will make the nipple stout. Advanced size is the most popular, yet some customers choose both sizes so they have the tools to better customize the shape of their nipples. Measurements - Beginner: 3 inches in length (not including tip), 1.125 inch outer opening diameter and 0.75 inch inner opening diameter.