ITEM NAME:Outside Micrometer Caliper Standard Calibration Measure Rod Bar 50mm+75mm Description: Outside Micrometer Standard Calibration Measuring Rod Bar Material: plastic; Diameter:Approx. 7mm Range: Approx. 50mm/2 inch; 75mm/3 inch; Accuracy:Â ±0.001mm Widely use for micrometer, micrometer caliper, microcallipers. Package Includes: 1 piece Micrometer Standard Rod(50mm) 1 piece Micrometer Standard Rod(75mm).Range: Approx. Accuracy:Â ±0.001mm.