Nighthawk Custom (FM Series) Match Grade Parts Kit brings all of the (FM Series) parts from Nighahwk into one package. An all inclusive kit to for customs or rebuilds that ships directly to your home. This is the same part that Nighthawk Custom Gunsmiths use in the build process, designed and manufactured in-house by Nighthawk Custom. Dimensions are intentionally larger then GI Spec to ensure a precision fit when installed by a gunsmith.