Caps are fully machined and assembled in the Midwest USA Diesel cap is billet aluminum, with stainless steel locking components. DEF cap is fully machined acetal, with stainless steel locking components. Keys are stainless steel with polypropylene handle. Only compatible with 2023 6.7L Diesel Ford trucks with diesel pipes as pictured (painted black inside). NOT compatible with 2024+ 6.7L Diesel Ford trucks. Locking diesel and DEF caps combo for 2023 Ford F250 F350 F450. Powerstroke only! This set only works for Powerstroke trucks with diesel pipes as pictured (painted black inside). If your 2023 model Powerstroke diesel truck has a bare stainless steel diesel filler pipe, you will need to order the set we sell for the 2021-22 model year Powerstroke trucks. CHECK CAREFULLY!