The Pantac WB-C021 measures 40x20x8cm. A small opening at the top lets the drink tube pass through. Outfit the pack by adding your favorite patch onto the large velcro. The extra pouch allows you to store accessories and fighting equipment. Carry this pack either by the sling, or attach it to the vest via the MOLLE platform on the back. Secret compartment lets you hide the back pack straps when used on a Molle system.