Expandable Storage (3L to 5L Expanded); Water Resistant Materials; Hydration Port for Water Bladder (Bladder and Hose Not Included); 5 Adjustable Hook and Loop Frame Mounting Straps; Multiple Bag Exterior Attachment Points; Capacity: 187 Cubic Inch Bag Volume (3L) / Expanded: 306 Cubic Inches (5L); Size: 5.5" Height (9" Expanded) x 17" Length x 2" Width