The ENVM/.. level controllers consist of:– a float suspended in the tank,
– a fixed roller to be fastened above the tank in such a way that the float is able to move freely up or down,
– a guide tube (to be fastened outside the tank) with a top-mounted fixed roller, internal counterweight with built-in magnet and with wall brackets,
– a rope tensed between the float and the counterweight,
– adjustable bistable magnetic switches of the type HMW/3/32 or HMW/1/32 mounted on the transparent PVC tube.