Vacuum pumps. It’s a device used to promote an erection by means of applying a suction force to the penis. This force is generated when the penis is placed into the device. When the erection is achieved, it’s necessary to fix an elastic band around the base of penis in order not to allow the blood flow out of the penis. This will help preserve a hard erection as long as the man needs it. According to the customer feedback, the pumps initially give good results. That is, the erection size and firmness are very satisfactory. But during the further use, the erections become much weaker. Penile injections. Such a method implies injecting special medications straightforwardly into the penis in order to cause the dilation of penile blood vessels. Due to this, the men can attain a desired erection. The injections don’t contribute to the increase in penis size. If the man suffers from a severe erectile dysfunction, injections are quite helpless.