Now with 35 % more power! This penis pump is a bit different – the Hydromax Hydropump is a hydro-therapy system that works using the natural strength of water. The hydropump can be used easily and safely in the bath or the shower. It makes impressive erections possible and can lead to a permanent enlargement of the penis. Transparent blue. Complete length of pump 30 cm. Inner Ø of opening 4 cm–6.8 cm. PC (polycarbonate), TPE, phthalate-free according to EU Regulation REACH.