The Starrett No.643 Jeweled Dial Depth Gauge is a precise measuring tool designed for metalworking inspection and measurement. With a range of .0005" to .125", this depth gauge allows for accurate readings of depth in microns. Featuring a jeweled dial for precise measurements, this gauge is a reliable tool for professionals in the CNC, metalworking, and manufacturing industries. The Starrett brand is known for its quality and durability, making this depth gauge a valuable addition to any workshop or inspection area.