A penis pump with a blue transparent cylinder in which you can see your results immediatly! Using the pump, you create a negative pressure in the cylinder, and flows more blood to your growing erection. You\'ll see how much bigger, thicker and harder your erection can get. The penis pump has a soft flexible silicone opening so that pumping is an erotic adventure by itself. features: Material: ABS, Silicone Plasticizer Free: Yes Color: Blue Height: 24 cm Diameter: 3.7 to 4.5 cm Operation: Ball Pump