An expandable bottom compartment accommodates more mission-critical gear. We carefully consider what is put in each of our bags and tailor the compartments, pockets and other features to make sure there is a perfect place for everything. Sometimes you need more space, while other times you need less. This bag expands to accommodate both. The coated 210 ripstop nylon and polyurethane zippers provide extra protection and water resistance. Includes an adjustable mounting system to fit most any bike. Construction: Water bladder hydration port included on drive font drive side. Installation: The included straps can mount in multiple locations for a secure fit. Water Resistance: Water resistant Extra protection against the elements Capacity: 4.3L/5.8L Expanded Dimensions: 457.2 x 177.8mm/279.4mm Expanded Weight: 360 grams