Xtreme Outdoor Power Equipment Replaces Swisher Mower PTO Blade Clutch 3813, ZTR50, Free Bearing Upgrade Xtremely cool coil design runs over 20% cooler for a longer service life  plus every clutch is backed by a buyer-protection 1-year warranty Replaces OEM: 3813 Replaces Warner: 5219-8, 3813 Specs: 1.000 Crankshaft, 5.4" Pulley, Counter Clockwise, 1/2" or 5/8" Belt, 125 ft. lbs torque Free Upgraded - High Temperature Bearings. TOUGH Machined Billet Pulley with Replaceable Bearing - OEM Upgrade