iGaging Digital Compass and Divider features inch/metric/fraction reading, smooth thread movement, interchangeable pencil lead, and metal scribe attachment. Speedbow Compass Combined with Digital Readout. Smooth Metal Thread – Efficiency of a Center Wheel Design. Large LCD Readout. Measure in Inches – Fractions – Millimeters. Convert Measurement between Decimal, Fractions and Metric. Zero Button gives the Precise Difference. Hold and Zero Set Functions. Ease to Switch from Divider to Compass Mode. Strong Poly-Fiber Jaws. Two Interchangeable Tips One Tube of Lead. Lightweight & Durable Poly-Fiber Jaws. Reading: 0.01″ – 1/64″ – 0.1mm (Display always shows radius). Accuracy: 0.01″ / 6″. Radius: 0-8″. Diameter: 0-16″. Material: Aluminum. Battery: 3V CR2032 Lithium Cell (included). Calibration Tool: Included.