With a total cylinder length of 20 cm (7.8) and a inner diameter of 6 cm (2.36), this high-quality pump gives you ample possibilities to grow in both directions! The insertion sleeve is made of smooth Silicone. Surprise yourself every time on how big you can get! At the touch of a button the extremely powerful pump will create a super-strong vacuum, giving you a quick and powerful erection. The soft silicone opening will create a tight yet comfortable seal. Takes 2 AA batteries (not included). Clinical studies have proven that vacuum erection devices will give instantly harder erections, cause temporary flaccid enlargement and can increase permanent penis augmentation. According to the American Urological Association, these devices may also be useful in cases where such PDE5 drugs as Viagra have failed to work! Doctors view the penis pump as a safe, effectual and cost effective treatment for erectile dysfunction and state that the prolonged use of these devices will enhance the size of the penis permanently. Other advantages of the PUMPED selection are, amongst others, delayed ejaculation, improvement of sexual appetite, boosting of testosterone, the maintenance of longer and harder erections and the supporting of penile tissue after prostate surgery. PUMPED, for instant results! WARNING: Please read product manual before using any type of vacuum pump or constriction ring. Stop using the devices immediately if you experience any pain or discomfort.