【Accurate Test Indicator】Measuring range: 0-0.03", Accuracy: 0.0005". Durable Brass Finish: High-quality brass body with anti-ic properties for long-term use 【ful ic Base】Two solid surfaces with on/off control can provide a maximum tensile force of 90lbs (40k) (90lbs tensile force requires a metal working surface/surface with a thickness of 30mm and above) 【Adjustable Holder Arm】Dimensions of 2 arms: lower arm 2.6"（6.6cm）; upper arm 2.7"（7cm）; total height 5.7"（13.6cm; Clamping diameter 3/8 inch ( 9.52mm). used for conventional digital/dial indicator; Flexible, sturdy, precise rotary joint, can adjust any direction and position, stability, Compatible with all most dials/digital indicators and other market indicators 【2 Measuring Rods】dial bore gauge set is equipped with 2 measuring rods. With one measuring range of 0.7-1.5" and the other measuring range of 1.4-2" and 1.5-6", you can change different measuring rods and probes according to your needs for measuring holes, bearing housings, pistons and engine s 【23PCS Anvils】The dial indicator bore gauge set is equipped with 23 different anvils: 0.7-0.8", 0.8-0.9", 0.9-1.0", 1.0-1.1", 1.1-1.2", 1.2-1.3", 1.3-1.4", 1.4-1.5", 1.4", 1.6", 1.8", 2", 2", 2.2", 2.4", 2.6", 2.8", 3", 3.2", 3.4", 3.6", 3.8", 4",so it can meet the needs of most of the inner diameter measurement