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.