Park Tool  DC-1 Digital Caliper

Accurately measures seat posts, head tubes, bearings, spoke diameters, etc. The DC-1 is a precision instrument built with stainless steel mechanisms and a rugged ABS composite body. The tool’s ability to measure in metric, decimal inch, and fractional inch make it an indispensable shop tool.
• Displays metric, decimal inch, and fractional inch to 1/128”
• Large LCD display
• Measures external, internal, depth and stepped dimensions
• Resolution: +/- 0.01mm/0.0005”/1/128”
• Accuracy: +/- 0.02mm/0.001 (-100mm)
• Repeatability: +/- 0.01mm/0.0005”
• Protective case and battery included
• Includes one battery, size SR44
• Automatic shut off