A device that applies even pressure to the penis by creating a vacuum. This can give the user an erection, and with enough pressure, the pump can increase the length and girth of the penis.

Penis pumps consist of a cylinder, usually made of plastic or glass, and a pumping mechanism, which may use air or water to create the necessary pressure. Many pumps also have gauges to allow users to monitor progress from one session to the next.

Penis pumps are sometimes recommended by physicians as a treatment for erectile dysfunction, especially for patients who have poor blood circulation due to diabetes or another disease. When used appropriately, pumps are safe, but excessive pressure may cause pain. Men with blood disorders such as leukemia should check with their doctors before using penis pumps.