The Sinclair Institute Vacuum Pump System. Overcome erectile difficulties with a vacuum therapy system that comes with two operating modes, an ergonomic hand pump and a battery-operated pump. Connect with the 2-inch cylinder, slide your penis in and pump to engorge your penis to its maximum capacity, hardness and size. Set of 4 constriction rings maintain the erection for up to 30 minutes. Comes with 2 pumps with quick release valve, 10 X 2 inch cylinder, removable gasket, connecting tubes, 4 constriction rings (.5 inches to .75 inches ), use and care directions. This pump is compatible with water-based lubes. It is not recommended to be used with silicone lubes. After use, carefully wash the pump with mild soap and water. Store this pump separately from other sex toys.