From the Manufacturer:
The fStop range embodies that unique Billingham combination of tradition and innovation. Designed for those times when you want to travel light, but still providing the high level of protection, style and craftsmanship you expect. Although they’re relatively compact, they can be easily adapted inside and out to suit your specific needs. These surprisingly spacious bags are ideally suited for modern digital or film equipment, from compacts to SLRs, even with lenses attached.
The first thing you’ll notice about both fStop models is their distinctive 'squared-off' look which is created by the insertion of a pleat on either side of the main flap. Look inside and you’ll find a secondary, padded lid that’s tailored to keep the elements out.
Billingham has purposely kept things simple and flexible inside and out, which also offers you the opportunity to custom fit your fStop to suit your changing needs from assignment to assignment. So, in addition to customising the interior layout, you have the option of extending the capacity of the bag by using the external AVEA Pockets, which attach securely to the sides of the bag via the solid leather straps, which also serve as the mounting points for the shoulder sling.
Should you need to carry a tripod, you can attach one by threading straps through the two sets of ‘D’ holes located under the main stud fasteners. Even with the AVEA Pockets attached, the fStop will still fit into an overhead locker on board an aircraft.