The TUNZE Osmolator 3 nano is a simple and safe device with just one sensor for maintaining a constant water level in aquarium systems up to approx. 250 liters (66 US gal.), can be placed in cabinet filter systems or directly on the edge of the aquarium. The sensor works on glass panes up to 12 mm (1/2”) . The hose holder holds up to 22 mm (0.87”) . Scope of delivery: ready to install with 12V power supply, low-voltage dosing pump, 3 m hose, hose holder, magnet holder up to 12 mm and protective cover for the sensor.