ITEM NAME:RC Car 540 550 Electric Motor Proof Cover Heat Sink Cooling Fan 1/10 Red Description: Made from high quality aluminium and plastic,for 1/10 RC racing car, 36mm diameter motor Two cooling fans protect the motor from overheating efficiently,easy to install Operating voltage: DC 5V 0.15A Suit for 1/10 HSP RC Car 540/550 3650 Motor Inside diameter: 34mm Package Includes: 1 x Motor Heat Sink With Two Cooling Fans.1 x Motor Heat Sink With Two Cooling Fans. Suit for 1/10 HSP RC Car 540/550 3650 Motor. Two cooling fans protect the motor from overheating efficiently,easy to install.