I just bought a 1950 8N tractor, and in order to use a shredder (as an example) you MUST have an overrun adapter! Once the PTO is engaged, it runs.... that is it! NO live PTO! Therefore, the PTO is tied DIRECTLY into the tranny! Without an overrun adapter, if you "clutch" the tranny, and attempt to stop... well good luck! The PTO and the centrifical force of the shredder will just KEEP going, and KEEP driving the tractor! See that tree? See that barn door? Too bad! Without an overrun adapter, you 'Aint-a-gonna" stop! THIS little guy will save your butt! It allows the "implement" to continue it's centifical force, and at the same time... it allows the tractor to "seperate" from the PTO (free-wheel) and stop! Simply put.. it is a ONE-way clutch, that allows your PTO to "Speed -up" under power, YET.. it disconnects (slips) from the drive-train for the "wind-down". A MUST have for older PTO tractors!

There is a pin that will need to accompany the unit. The pin is inserted through the grease zerts holes. the pin prevents the unit from falling off the tractor PTO shaft. Mine did not come with a pin! Therefore I will have to make a return trip to the store to locate a pin!