Introducing the Worlds First Water-Based Penis Enlarger. The bath mate is set to take the world by storm, being the first ever penis enlarger based on hydraulics. Bathmate is the worlds first water-based penis enlarging device. Unlike other devices on the market, Bathmate gives instant and sustainable results and in most cases is pleasurable and comfortable to use. The bathmate uses powerful water technology to create the ultimate vacuum force, utilising Hydraulics in reverse, making it the most powerful pump in the market.