This aluminum clutch disk is an inexpensive alternative to the stock/OEM disk for pulling. It is most widely used in the lower hp tractors and in the beginner's classes. The disk is machined out of billet aluminum and works because the aluminum is softer than the steel pressure plates creating a strong bond. It is recommended to have the pressure plates surfaced/replaced to use this style disk to get the maximum surface area. This disk cannot be slipped. Slipping will gaud the disk and create small aluminum filings in the pressure plates.