a fine-adjustment carriage to fine-feed the slider for heavy duty series. Vernier Caliper made of carbon steel, the has clear and is durable. Stainless Steel Vernier Caliper is , it can measure outside dimension (OD), inside dimension (ID), step, and depth a multifunctional tool. Durable manual caliper with smooth slide. It's convenient to use with one hand without. Engraved scale easy to read.