Item: 550/540 Size Electric Engine Motor Heatsink Part No.: 7014 Package Include: 1x 550/540 Size Electric Engine Motor Heatsink Features: Powered by DC voltage:5V-6V Keep your temperatures in check and your motor running efficient and cool with our heatsink and cooling fan combos. designed to be powered by DC voltage only between 5.0V and no more than 6.0V MAXIMUM! If you choose to power our cooling fans with voltage exceeding 6.0V you are doing so at your own risk! Please make sure that your power source (battery pack, receiver, etc.) is able to supply consistent voltage no lower than 5.0V and no higher than 6.0V. If powering from an ESC, check with the ESC manufacturer to make sure if your ESC is capable of providing enough auxiliary power to handle the added load of extra cooling fans; some ESCs that have built-in fans may not be able to reliably power any additional cooling fans. Compatible with:550/540 Size Electric Engine Motor Note:Check your specific model's manual for compatibility,or Contact us.