as other have mention this bag hold a lot of gear . one of the biggest selling point for I be that be that be can be use as you second carryon on a airline . as big as it be , it be design to fit under the seat , so it count as you hand hold carry on . I have travel with it many time and never have to gate check it . it be a little tight on the commuter plane , but I have always be able to carry it on to the plane with I . generally I have two camera body and a assortment of lens , flash etc. . it have separate compartment for extra flash card and battery as well as a few other pocket useful for battery charger , note book etc. .