emptasia Nipple Pumping Cylinders are compatible and interchangeable with other Temptasia pumps and accessories. In use with a quality pump, they'll bring temporary engorgement and heightened sensitivity to your nipples. The cylinders are crystal-clear for easy viewing, plus detachable if you are seeking to hold the suction while you play. This size cylinder, 0.75" inner diameter, is a comfortable medium size. Made of body safe acrylic, Temptasia Cylinders are easy to use and easy to clean.