Efficient Heat Dissipation:The motor heat sink is designed to provide cooling for your motor, ensuring optimal performance and longevityVersatile Compatibility:This heat sink is originally designed for the stock motor but also offers compatibility with Castle 1717 motors, making it a versatile choice for various setupsHigh Speed Double Fans: This cooling system with double high speed fans offers adjustable fan speeds ranging from 6000 RPM at 6V to an impressive 14600 RPM at 12V, providing cooling based on your power needsMaterial:Made from metal this High Speed Cooling Fan nsures durability and sturdyEasy Installation: These motor can be easily replaced or installed without any tools or expertise required Size Chart: fan : 4X4X2.8CM/1.57inchX1.57inchX1.10inch rack A : 7.9X4CM/3.11inchX1.57inch rack B : 6.2X5.2CM/2.44inchX2.05inch Package Includes: 1 SET RC TruckMotor Heat Sink Note: Color might be slightly different due to the color calibration of each individual .Please allow slightly measuring deviation due to manual measurement.