Each cylinder is meticulously crafted from high-quality, industrial-strength, crystal-clear acrylic. The calibrated scale on the side helps you track your size and progress over time. Each cylinder features a cutting-edge air valve that enables quick and easy disconnection from the pump while keeping the pressure intact. Most men will need the 2-inch diameter cylinder. If your size is on the smaller side, we suggest the 1.75-inch diameter cylinder. Conversely, if you are above average, the 2.25-inch cylinder would be ideal. Compatible with all pumps, hoses, cylinders, and valve pumping systems that utilize the valve interconnect system, such as LuvPump, Size Matters, LA Pump, Pumped, etc. This is a cylinder only; you will also need to purchase the pump with hose for connection. Size: 2.25-inch diameter x 12 inches long.