With 7/8" Washer To Prevent Overdrive And To Increase Holding Value When Fastening Wood Or Thin Metal To Concrete Or Structural Steel. Fits All Ramset, Hilti, Remington And Most Powder Actuated Tools That Use 22cal. Single Shots, 27cal. 10 Shot Strips And 25cal. Discs. 0.145" Shank Diameter.