Like the Bathmate Hercules the Goliath uses water to maintain pressure to stretch and engorge the penis to enhance and enlarge the penis. This product is getting rave reviews all over the world and can be used in the shower or bath. This is one of the biggest penis pumping systems we have ever seen at the Warehouse, and they are beautifully constructed. So if you are looking for a larger pump then the Goliath is well worth a look. Bathmate say that by using water rather than air you get a much more consistent pressure and less risk.