This Faithfull D.I.Y Vernier Caliper is manufactured from mild steel, with dual reading in imperial and metric. The universal three-way measurement facility enables readings in external, internal, and depth modes. The caliper's sliding thumb-lock feature allows easy, quick, and precise measurements to be taken. The metric and Imperial dual reading comes with a handy locking function, the dual reading comes in 1.0mm and 0.16in increments. Range 125mm (5in).