The Inch Screw Checker is a precision threaded tool for complete instant identification of UNC & UNF screws. This quality tool made of heavy-gauge steel is satin-chrome plated, expertly machined & American made! All do-it-yourselfers, handymen, mechanics and maintenance people have too often experienced the frustration and loss of valuable time and money by mistakenly identifying a screw. With this easy to use, pocket sized tool you can kiss those problems goodbye! No more headaches, cursing, and multiple trips to the hardware store! Unlike their plastic counter parts, these screw checkers, made of heavy gauge steel, will last for a very long time without the worry of wearing out the threads after a few uses.