STM Husqvarna 450 510 610 Slipper Clutch. Required reading for a life of backing it in effectively without wheel hop and slippage coming out of hot corners. Material: aluminum alloys and special steel Primary spring: Material: aluminum alloys and special steel Primary spring: 125 mm Evoluzione diaphragm spring code 003SUZ119 Secondary spring: 85 mm Evoluzione spring code 0F3SR540B140006 Basket: original Husqvarna (not included) Features: slipper system - device to control the opening Compatible disc pack: original Husqvarna (not included) The Controlled Engine Braking System (CEB) uses advanced clutch technology bringing new and innovative performance improvements to the rapidly expanding 4-stroke Off-road, Super Moto and ATV markets. All components of this system are produced utilizing the highest quality manufacturing standards-ISO 9002-and Italian craftsmanship by STM. The CEB Clutch System is a unique and highly effective engine-to clutch-to rear wheel power management system; the only one of its kind available anywhere. When the throttle is closed, this triggers the clutch to release and decreases unwanted engine braking. Already in use by top factory riders and teams, it decreases lap times, inhibits engine stalling, increases holeshots and helps create 'neutral' jumping characteristics by decreasing rear wheel drag in 'throttle off' conditions.