Feature:1. Heat sink specially designed for 540 550 3650 3660 RC model car engine.2. Heatsink with thermal sensor RC equipped with 5?11V cooling fan, to your engine.3. Temperature sensor will accurately detect temperature rise, when engine temperature rises to 40?, cooling fan will automatic turn on to cool engine.4. Cooling fan can power supply over receiver, convenience and easy to use.5. Heat sink adopts high quality materials designed clamp shape and exquisite workmanship, and can used for a long time.Spec:Condition: Brand NewItem Type: Motor Heatsink Cooling FanType: RC AccessoryMaterial: Aluminum Alloy + PlasticOptional Color: Black, Red, Golden, BlueFan Voltage: 5-11VFitment: Suitable for /Hsp/Redcat//Axial scx10 D90/Hpi Brand UsingQuantity: 1PCSWeight: Approx. 26gFan Size: Approx. 30x30mm/1.18x1.18inchSuitable: Brushless Motor 3600 Serial Size UsingBrushless Motor 550/540 Size UsingPackage List:1 xMotor Heatsink Cooling FanNote:1. Due to manual measurement, please allow 1?3mm error, thank you for your understanding.2. The display calibration is inconsistent. The color of the item shown in the photo may be slightly different from the actual object. Please refer to the real one