This is a replacement Traxxas Hoss Cooling Fan Kit with Shroud, intended for use with the Hoss 4X4 VXL 4WD Monster Truck. This fan fits the TRA3351R Velineon 3500 Brushless Motor and the TRA3461 Velineon 540XL Brushless Motor. The TRA3458 Velineon 540XL Motor Heat Sink is required for installation.