The Size Matters Breast Enhancement System is exactly what you need to give yourself fuller breasts. Each cylinder is made of industrial strength crystal clear acrylic and will fit comfortably over your breasts. With this system you can enhance your breasts to a nice full size in no time Just fit the cylinders over each breast and start pumping. Use the gauge to help get you to your full potential Kit contains premium handle pump with gauge, split connector hose, and 2 air lock breast cylinders. Measurements: Cylinders are 4.5 inches inner diameter and 4.25 inches deep, Material: Acrylic, PVC, ABS, Metal