General Tools 714 Quick Check Screw Gage Quickly identify machine screws, bolts, wood screws, standard sized rivets, and common cotter pin sizes Checker also gives required drill size for corresponding tap size and proper drill size for like hole Threaded holes indicate threads per inch while unthreaded indicates size by number and fractions of an inch The 3 inch scale allows checking of screw lengths; the checker is engineered with durable engineering plastic Made in the USA Quickly identify machine screws, bolts, wood screws, standard sized rivets and common cotter pin sizes Quickly identify machine screws, bolts, wood screws, standard sized rivets and common cotter pin sizes Checker also gives required drill size for corresponding tap size and proper drill size for like hole Threaded holes indicate threads per inch while unthreaded indicates size by number and fractions of an inch The 3 inch scale allows checking of screw lengths; the checker is engineered with durable engineering plastic