Evolution LSD is an upgraded version of the popular Salisbury clutch type LSD. It has improved clutch material and a unique design for smooth transitions between loaded and unloaded. Extremely easy and predictable to drive. The first number is the deceleration ramp. 90 degrees deceleration ramp gives no drive, second number is the acceleration ramp. 35 degrees acceleration ramp shallower angle gives more drive, their round cross-section and matching curved ramps facilitates changes to the locking action on acceleration and deceleration of the diff.