Control circuit, the pump is more stable. Great for PC CPU cooling system. Tap out the instructions marked. Small 3P power connector can be directly plugged into the headboard fan original position. Support speed testing function. With rubber base, ultra-quiet experience. With high quality and durable performance. Flow: max300L/h Head: max1.9 Power connector: small 3P connector Voltage: DC12V Power: 4W Water tank capacity: 150ml Noise: 23DB Dimensions: about 66x56x86mm(net size, excluding out of faucets, ) Tap diameter: about 9.4mm Colour: as shown Material: ABS Package Contents: 1 * Ultra-quiet Water Pump Set Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.