SPI Internal Dial Caliper-Type Gage For checking internal bores and recess diameters. This gage offers a total movement of 1" (25mm). Features include... 3.250" - 4.250" Measuring Range 0.001" Graduations 3.25" Arm Length 0.06" Measuring Tips Spring loaded opening Bezel Rotates for Zero-Setting Button for closing arms. Arms automatically open when button is released Unit is spring-loaded and makes point contact at constant measuring pressure
