Hydro Penis Pump. The Hydromax Hydropump is a hydro-remedy system that works utilizing the pure energy of water. The hydropump can be utilized simply and safely within the bathtub or the bathe. It makes spectacular erections doable and may result in a everlasting enlargement of the penis. Transparent. Complete size of pump 26.5 cm ? appropriate for a max. penis measurement of 14.5 cm (when erect). ? 5 cm. Material: PC (polycarbonate), TPE.