Fully expandable from 16L to 26L (approx)Water resistant fleece lined audio pocket with headphone exit portHidden helmet carrierHeavy duty reinforcementsYKK® Auto locking zippers applied on main compartment opening for secure closureSternum Map panel holderInternal Lap Top sleeve which fits most 15 in. lap top computersInternal organizer pocketsInternal sleeve for Bio Armor Back Insert applicationBuilt in Rain CoverAdjustable Waist strap