F1 Racingbs Chromoly Flywheel 54021FX-HT Ultra heavy-duty and weighs only 8.5 lbs Meets or exceeds SFI 1.1 specification Made from 4140 forged chromoly steel (2X stronger than billet steel) Incorporate special design features to enhance the airflow for improved clutch cooling Work with every clutch including Exedy, ACT, Fidanza, Clutchmasters, and other direct replacement clutch kits