The Osprey Flap Jack has so many features it's not true. It has a capacity of 20l and made of a durable, showerproof fabric which is nice to the touch. The main strap isn't the longest however still adequate reaching to the hip at full length. It does have a quick release buckle to shorten/lenthen the strap, potentially very useful in the cold or wet. The shoulder support is long, wide, comfortably padded and has 'osprey' in grippy silicone letters on the underside to reduce slippage on the shoulder.
The exterior of the flap has a large hand-sized zipped pocket, there is another zipped pocket at one side of the main body which easily accomodates a travel mug, 500ml bottle (750ml just) or food flask. There is a narrow hip belt on the rear which can be removed if required, handy for cycling or if the bag is especiialy heavily packed. Another nice feature for cycling is a blinker patch to attach a light just below the closed flap.
The flap is secured by velcro and for added security has two user friendly buckles. The webbing for the buckles are interchangeable, it comes supplied with grey, blue and green. There are grab handles on the top of the main body, one interior and one exterior.
The interior is bright lime green (for the black version), not to everyones taste but it does help in finding things. There is one large storage compartment approximately 40 x 15 x 30cm, it has a elastic mesh pocket in the side suitable for securing a water bottle. There is a velcro secured, padded laptop sleeve compartment which will fit A4 folders, and a similarly sized, thin, zipped mesh pocket.
Under the flap there are two generous zipped pockets with some minimalist organization, including a keyclip, and card and pen holders. The bag is lightweight, with the zips, construction and stitching all excellent quality.
A superb bag, suitable for various activities, highly recommended.