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. !!!NOT compatible with 2021, 2022 or 2023 models!!! Locking diesel and DEF caps combo for Ford trucks with 6.7 L POWERSTROKE engine. This is designed for the 2017 model year. This is compatible with 2012-2014 filler necks, and 2017-2019 filler necks. SOME 2015, 2016 and 2020 filler necks are compatible. Check carefully.