High Visibility Tool Vest with Built in Hydration Pouch - Electricians, Surveyors, Contruction (Black) Designed for Construction Harness to be worn underneath vest Made1280 D Nylon - in USA and Imported Evenly distributes tool weight on the upper torso. Pocket on the back that will hold a 2 Liter hydration pouch. Built-in back support belt / Size adjustments to customize the vest from 40" - 60" around the chest.