Doc Hardman's powerful penis pump operates with an electric vacuum pump and is ideal for helping men achieve and maintain an erection, or for penile enlargement....... The kit comes complete with an 8” clear plastic penile cylinder, 3 silicone restriction rings in various sizes, soft material donut for comfort and detailed instructions and a black leather-look carry case for portability. Easy to operate, it simply requires the touch of a button, there is no manual pumping required. The pump is also superquiet for discreet use.