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 protect 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, durable and can used for a long time. Specification: Condition: 100% Brand New Item Type: Motor Heatsink Cooling Fan Type: RC Accessory Material: Aluminum Alloy + Plastic Optional Color: Black, Red, Golden, Blue Fan Voltage: 5-11V Fitment: Suitable for Traxxas/Hsp/Redcat/Tamiya/Axial scx10 D90/Hpi Brand Using Quantity: 1PCS Weight: Approx. 26g Fan Size: Approx. 30x30mm/1.18x1.18inch Suitable: Brushless Motor 3600 Serial Size Using Brushless Motor 550/540 Size Using Package List: 1 x Motor Heatsink Cooling Fan Note: 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