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 shock absorber base, ultra-quiet experience.With high quality and durable performance.Flow: max300L/hHead: max1.9 metersPower connector: small 3P connectorVoltage: DC12VPower: 4WWater tank capacity: 150mlNoise: 23DBDimensions: about 66x56x86mm(net size, excluding out of faucets, shock absorber)Tap diameter: about 9.4mmColour: as shownMaterial: ABSPackage Contents:2 x Ultra-quiet Water Pump SetOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.