Hays heavy-duty Flexplates for high performance and competition Cummins Diesel engines are constructed of a thicker than stock steel plate, enabling them to withstand the stress of today's high-torque engines. While factory stock Cummins Flexplates tend to crack or even shatter when punished under high torque and RPM conditions, the thicker Hays Flexplates handle the additional brute force. All Hays heavy-duty Flexplates are either zinc-dichromate plated or black oxide finished to resist corrosion. Also all of Hays' Flexplates are SFI certified under specification 29.1 or 29.3 depending on application.