Mitutoyo 500-473 Absolute Digital Caliper, Stainless Steel, Solar Powered, Inch/Metric, 0-4" Range, -0.001" Accuracy, 0.0005" Resolution Hardened stainless steel construction for protection of caliper components Solar-powered for continued use without battery replacement Hard-coated solar panels for increased durability in energy storage solar cells and safe operation Four-way measurement capability for multiple applications: outside diameter (OD), inside diameter (ID), depth, and step Digital, single-value readout LCD display in inch or metric units for readability