Economy rolling track standard gauge reader measures up to 2-inch gauge variation while walking down the track (56 to 58-inches for standard gauge track). Spring-action telescopic assembly expands and contracts as gauge changes. Worker can read gauge while walking by looking down at a lens and gauge scale. Insulated, steel roller bearings provide smooth travel and side rollers measure gauge at 5/8-inch below top of rail to avoid burrs. Passes over rail joints but cannot roll through rail crossings or switches. Clearance above rail: 1/8-inch. Scale can be calibrated to a specific gauge before starting out to inspect the track. Weight 33 pounds. Product of Aldon® Company.