Gauges, setting plugs and check plugs for standard Unified Coarse (UNC), Fine (UNF) and Unified Extra Fine (UNEF) threads (BS 1580:Parts 1 and 2). $7IGo$7R and $7Inot go$7R screw plug, solid screw ring, adjustable screw ring, and adjustable screw caliper gauges; double length setting plugs for $7Igo$7R and $7Inot go$7R adjustable screw ring gauges and single length setting plugs for adjustable screw caliper gauges; $7Igo$7R and $7Inot go$7R plain plug and caliper gauges for the crest diameters of product threads.