HO Scale Coupler Height and Multi-Purpose Gauge205 Package Contains: one HO scale multi-purpose gauge body, one no.5® coupler, one 58 Scale Metal Coupler, one 2-56 x 5/16” self-tapping screw, extra 625 knuckle spring, extra 622 knuckle springs, and ten 208 (.015”) red washers.EASY TO ASSEMBLE & USEIncludes the No5® Coupler & 58 "Scale" Coupler. A must have tool for gauging correct coupler height, trip pin, and permanent uncoupler heights for achieving trouble free coupler performance. Also has a built in HO track gauge. "Takes the guess work out" Multi purpose gauge.Four tools in one.1. Provides instant visual reference of proper coupler height.2. Accurately measures proper trip pin height above rail.3. Built-in track gauge.4. Movable dowel tests Kadee® Magne-Matic® Uncoupler height and registers the needed adjustments.NOTE: The 205 gauge is not insulated and “only” should be used on a nonpowered track or track with the electrical power completely switched off.