Heat is the enemy, especially when it comes to electric motors. Keep your temperatures in check and your motor running efficient and cool with our Motor Heatsink with Twin Cooling Fan. The motor heatsink clips right onto your 540 or 550-sized motor, and features an anodized coating and multiple heatsink fins for added cooling surface area. The cooling fan is powered through a standard 2-pin Rx plug. NOTE: The power source connected to the included cooling fan should NOT exceed 6VDC. SPECS Length: 2.4" (61mm) Width: 1.57" (40mm) Height: 1.65" (42mm)