The merlin reverse osmosis unit is operated using only tap water pressure (3-4 bar) without necesisdad of a pump, has two membranes and cartridge combined flow of coal and sediment. It has a salt rejection of 95% and a recovery ratio of 1:3 - 3:5 (pure water / waste water). The body of the unit is assembled and ready to go. We recommend using the level controller with a M ventil Aquaniveau ½ "to have the automatic control unit.