This double cardan style CV driveshaft is necessary for JK models equipped with 3.5" - 6" short arm suspension lifts or 2.5" - 6" long arm suspension lifts. It features a replacement flange for the differential pinions as opposed to using an adapter flange. These flanges are machined from solid billet steel. They are designed to accept standard "off the shelf" mating flanges. If these flanges ever break, you at least stand a chance of getting a replacement part from almost any drive line shop. This also nets a longer drive shaft with the center of the universal joint closer to the pinion bearing.