In addition to this, a constriction ring is added to the kit of penis pump, which is responsible for maintaining the erection achieved by the male. The pump is often compared to various products that tend to increase penis size as well, such as penis extenders.
In terms of penis enlargement, there is no assurance that penis pump may work for permanent growth. The only evidence it could present is in relation to erection. However, for permanent growth, there is limited information that could support the efficiency of the device.