Drain plug with built-in field sensor switch. It connects to the Gulper IC pump by means of a 4-m cable with watertight quick plug. It activates the pump as soon as water flows into the drain. This system allows to drain off grey waters with no need of activating a control before using the shower or sink. Small size, sturdy materials, no maintenance or cleaning required. Check-valve included. Fittings for 19- and 25-mm hose.