Ducabike DBK CFD105/D08 Hyperstrada 821 Adjustable Cartridge Kit519467656 Short Description Product Description Complete hydraulic fork cartridge kit to replace your original equipment. Andreani have developed a sophisticated hydraulic system that ensures exceptional performance. Using 20mm pistons for increased oil flow you have a front fork that has considerably more feel and control than standard. The kit comes with adjustable spring preload and complete with springs to suit ride 20mm diameter pistons.