This is a cylinder with a rod running down the center and extending outside the cylinder. Lube the rod and the end of the cylinder with a thick lube to provide a good seal, insert the rod into the anus until the end of the cylinder presses against the anus, and start pumping. Cylinder is available in only one size and includes a quick connect/disconnect safety valve that maintains vacuum pressure after you disconnect the pump. Including a partner in these activities is recommended for ease of use and safety. Requires the LA Pump and hose, sold seperately. The cylinder measures 6.5 inches long and 3 inches diameter, and the rod is 10 inches long and 1 inch thick.