The Hydro 7 (formerly known as the Hercules), is Bathmate’s original, best selling penis pump, with over a million sold since it was first launched in 2006. With its revolutionary design and impressive results, this easy to use device enables you to gain all the benefits of pumping for penile health and well being. The Hydro 7 is particularly recommended for beginners as a safe and convenient way to practice penile rigidity exercises. Designed for use by men with a current penis size of 5 to 7 inches when erect. Length 11.7 inches. Canal diameter 2.1 inches.