SPI Electronic Internal Caliper Gage This type of gage is perfect for measuring bores, internal grooves, and other hard to reach inside dimensions. Specifications include... 1.2" - 2.0" / 30-50mm Measuring Range 0.0005" / 0.01mm Resolution +0.0008" / 0.02mm Accuracy 1/16" Ball Contact Point 3.150" Arm Length 0.335" Tip Length 0.118" Tip Width Features include... Preset Origin for absolute measurement Origin data recall Absolute and incremental measurement Dial rotates 170° Auto power off Furnished in aluminum case Certificate of Calibration