Pumps are quite popular among men who seek to enlarge their penis; however the results with a penis pump are temporary, lasting only a few hours, if that. There is also no boost in vitality or stamina; in fact, overtime your ability to get hard and stay hard without a pump can become worse. Some have had very painful burst blood vessels when the penis is over pumped. The guarantee is usually a one-year product replacement guarantee, not money back. Customer satisfaction is on the lower end of the scale mostly because it is very awkward to use a pump in the moment of intimacy.