Those are for the pro-drives which we have on our 1790 planter. See the first pictures in the original post. On the DB planter we have the chain drive system. The chain drive system requires the clutches that go on the drive shaft. To use box style clutches we would have to change our planter over to the pro-drive system and I didn't see the need for that additional expense. I don't see that the pro-drives work any better than the chain drives in our situation.

John