True high performance front suspension is finally available for the HD 49mm front ends. Progressive Suspension has gone back to the drawing board and created a state of the art Fork Cartridge Kit designed to outperform everything on the market.   Our new asymmetrical design places a preload adjuster over a progressive rate spring in one leg and an aluminum bodied, sealed cartridge damper on the other. The result is superior damping and ride control combined with tunable preload and a new benchmark for high performance suspension on the 49mm Dyna and Sportster platforms. Can be installed in either configuration, Standard or 1" low available for 2006 Dyna applications and 2016 Xl 48 models.