NcSTAR Vism Backpack Adjustable compression strap top to bottom Middle compartment dimensions: 16"H x 8.25"W x 2.5"D Heavy duty carrying straps Main compartment dimensions: 17" H x 8.75" W x 4.5" D Durable PVC construction Heavy Duty zippers; Heavy Duty carry straps on the top of the back pack Adjustable Compression strap (top to bottom) and on each Slides of the back pack Adjustable Sternum and Waist straps with quick snap buckles