High Torque Coil: This OEM Upgrade is 175ftlbs of Torque (OEM Torque is 150 ftlbs). Higher Torque Means this Clutch holds Strong Even in the Toughest Cuts and Prevents Overheating caused by slippage. BIGBearing: The Pulley Bearing Takes a lot of abuse and is often the first thing to fail. We use a Larger Pulley Bearing for a much longer life. We also designed our Billet Pulley with a snapring making the bearing replaceable. Heavy Shielded and Replaceable Wire Harness. Tough Billet Pulleys: Billet Pulleys Reduce Belt Wear and Maintain Perfect Blade Speed. Our Billet Pulley Design uses a Snap Ring and Allows for Bearing Replacement. Premium C3 Bearings: To Combat Heat HD Designed and Spec’d these bearings with C3 Clearances, Premium High Temperature Grease and on Most Models a Larger Tougher Bearing. Fits: 991060, 991061, 991062, 991063, 991064, 991067, 991076, 991077, 991078, 991079, 991080, 991081, 991095, 991096, 991097, 991102, 991103, 991104, 991115, 991116, 991117, 991119, 991120, 991121, 991122, 991123, 991124, 991125, 991126, 991127, 991128, 991129 HD Clutches are designed at HD Clutch and Assembled in the USA. Higher Torque: 175ft-lbs (OEM is 150 ft-lbs). We add a few more windings to our coils to provide the maximum gripping strength to prevent damaging micro-slipping during tough cutting conditions. The HD Switch BIGBearing design addresses the #1 reason clutches fail with a larger tougher pulley bearing. Machined Billet Pulleys: It is easy to damage formed pulley and damage (even a small stone nick) damages the belt with every rotation. With our Billet Pulley design, we include a snap ring so the bearing is replaceable, making this clutch rebuildable. Clutches all run very hot; we use a composite material instead of plastic to allow the heat to dissipate much faster. This makes the HD Clutch run much cooler; extending the bearing and clutch life. HD Clutch wrote the Bearing specifications to include Premium C3 Rated Bearings and high temperature rated synthetic grease to combat heat. Less Heat = Extended Life.