Automatic Head Pump Clear. Easy to use, incredible suction. Automatic pressure control. Auto start, stop. Quick air release button. Ergonomic hand held controller with push button controls. Easy to read LED display measures PSI vacuum inside compact cylinder. Flanged base for a secure seal. Safe and pure for body and pleasure made using phthalate free materials PC poly-carbonate cylinder, ABS plastic with polyurethane PU Cote controller, Thermoplastic Rubber TPR donut, Silicone hose. 4 inches by 2 inches cylinder. Penis pump requires 4 AAA batteries, not included.