Features:1.The RC heat sink with thermal sensor is equipped with 5-10V double cooling fans to protect your motor.2.The thermal sensor will accurately detect rising temperature, when the motor is up to 40℃.3.The double cooling fans will automatically turn on to cool the motor.4.The double cooling fans can be powered up from the receiver, convenient and easy to use.5.With high quality material and exquisite workmanship, the heatsink is durable for long term use.Descriptions:1.This RC motor heat sink is specially designed for 540 550 motors of RC model car.Specifications:Item Name: Heatsink Double Cooling Fans with Thermal SensorColor: Red,Black,Blue,Purple,Silver (Optional)Fan Input: 5-10VFan Size: 30 * 30mm/pcsClamp Suitable for: 540/550 MotorsFan: Single FanPackage Information:Package Size: 90x130x40mm/3.51x5.07x1.56inPackage Weight: 30g/1.05ozPolybag PackagePackage Included:1 x Heatsink Single Cooling Fans with Thermal SensorWe offer 100% money-back guarantee within 30 days free replacement. You're taking no risk with your purchase. If you have any problem, just feel free to contact with us.