This type of adapter is used for 6 lug 135 bolt pattern truck to fit 5 lug 135 bolt pattern wheels. CNC machined billet aluminum and 2" in thickness. New wheel studs are included. Mostly used on 6 lug Expedition/Navigator (03-on) and F150 (04-on) truck, so that 5 lug Expedition (00-02), Navigator (97-99) or F150 (97-04) wheels can be installed. This is a 2 piece combination adapter in order to solve hole overlapping issue.