Supports the following standards: ASTM D2937, ASTM D560 May be used for outside, inside, depth and step measurements. Switchable from inches to millimeters. H-2816: Digital Caliper, 6", Range: 0-6" (0-150mm), Accuracy: ±0.001" H-2816C: Calibrated- Digital Caliper, 6", Range: 0-6" (0-150mm), Accuracy: ±0.001" H-2816.8: Digital Caliper, 8", Range: 0-8" (0-200mm), Accuracy: ±0.001" H-2816.12A: Digital Caliper, 12" (300mm), Range: 0-12" (0-300mm), Accuracy: ±0.0015" (0.025mm)