SCREW CHECKER GAGE #1 MACHINE SCREW TO 5/16" FRACTIONAL SCREW Features all the information you need for screws, fast and convenient, diameter, length, threads per inch, hole size, even tap & drill sizes. Inch Checkers: Quickly and easily identify unified and American threads. Checks wood, sheet metal, self-tapping screws, plus bolts, rivets and many cotter pin sizes, NC, NF, and NS threads. Made in USA
