silent operation Suitable for aquarium, chemicals, liquids, dosing additives it is very easy take apart and clean, just pull out and push in is ok Specification: Volts: DC 12V current: 80mA working condition: 0-40 flow rate: : 0-100 ml/min rotate speed: 0.1-100 rpm driver size(x H): Dia.27.6 x Height 37.9 (mm) powerhead size(x H): Dia. 31.7 x Height 20.1(mm) silica gel tube(IDxOD): outer diameter 4.7mm,inside diameter 2.5mm flow direction: you can control the flow direction by the positive and negative connect