The motor heatsink clips right onto your RC vehicle's motor, and features multiple cooling fins for added heat-dissipating surface area.
IMPORTANT FAN VOLTAGE NOTE:
All Integy heatsink cooling fans, unless specified otherwise, are designed to be powered by DC voltage only between 5.0V and no more than 6.0V MAXIMUM! If you choose to power this cooling fan 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. 

Fits: 540/550 Motors