Hardened stainless steel construction with satin chrome finish, for protection of caliper * Measures outside dimension (OD), inside dimension (ID), step, and depth (when depth bar is included) * Raised sliding surfaces to help prevent defacement and wear of scale graduations * Modest, 14-degree face angle on vernier scale, for improving visibility and reducing the possibility of parallax errors * Meets Federal Accuracy Specifications GGG-C-111B