This is the Castle Creations Fan Shroud, intended for use with Neu-Castle 15 series motors, as well as motors that have outside diameters between 1 1/2" and 1 7/8". Pushing your Mamba Monster to the max? Just the type who likes the motor as cool as possible? No matter which category you fall under, Castle has the solution! The fan plugs directly into your receiver for power, and can drop motor temperatures as much as 30 degrees!* A must have for any hardcore basher! Your Mamba Monster will love you for it!