In general, there are usually three types of men who are interested in using a penis pump – men who are suffering from erectile dysfunction, men who want to use the device to have a bigger penis, and men who require penile rehabilitation. Penis pumps also called negative pressure or vacuum erection devices, are easily available online and through the medical community. There is a plethora of advertisements for these devices making all sorts of claims. Many manufacturers and distributors promise longer, harder erections and exceptionally satisfied sexual partners. What does a penis pump do? Does it increase the size of the penis? And do penis pumps work? Can they fix erection problems? Let’s find out what the scientific evidence shows.