Fidanza Lightweight Aluminum Flywheels for your Toyota, Lotus 1ZZ-FE & 2ZZ-GE engines or 2ZZ-GE swapped vehicles. This flywheel is USA Made, CNC machined from 6061 T6 billet aluminum. The replaceable friction surface uses a 1050 high carbon, alloy steel, secured with 16-20 hardened aircraft quality screws with self locking nuts which prevent any warping. Fidanza uses hardened ring gears that are swarted to the flywheel with button head screws that are counter board between the flywheel and ring gear to prevent any possible slippage. The mass at the center of the flywheel is retained for strength, but the mass at the outside is eliminated for optimum performance.