The SerfasA(C) Ark Expandable Half-Frame Bag can adapt to accommodate more gear with an expandable bottom and resists the elements with a durable water resistant construction. Thirsty? Pack your favorite hydration bladder and utilize the integrated Hydration Port routing. Features: Expandable Storage (3L to 5L Expanded) Water Resistant Materials Hydration Port For Water Bladder (Bladder & Hose Not Included) 5 Adjustable Hook & Loop Frame Mounting Straps Multiple Bag Exterior Attachment Points Specs: Size: 5.5" Height (9" Expanded) x 17" Length x 2" Width Capacity: 187 Cubic Inch Bag Volume (3L) / Expanded: 306 Cubic Inches (5L) Color: Black