The 1911 Fixture Block fits the 1911 Armorer Plate (sold separately) to allow the armorer to fit and dress all parts of the handgun. The 1911 Fixture Block is a must have for performing a number of inspections to guarantee your 1911's are in perfect working order. FeaturesCheck trigger sear fit Holds Grip safety to dress trigger bow interfaceHold Thumb safety to dress for plunger interfaceHold Thumb safety for sear interface inspectionHold Frame for ease of sear & disconnect installation