Awesome and pretty rare Swiss XL rucksack. The guy I deal with in Switzerland says it was for transporting bulky comm's gear. Just for the record, I wanted to break down the project into the many steps and stages that made this great piece of history a little more modern, it's 44 years old this year, 1973-2017. This is a large Rucksack, twice the size of the popular Salt & Pepper Swiss rucks. OD green canvas, very thick, the suede bottom is heavy gauge as well. Weighs in at about 6lbs. very heavy duty rig. Same internal frame design as the other Swiss rucks, steel stays are spring steel, super tough to drill for my hip belt upgrade. You can see the stitching for the stays above. Inside, below, they are inside canvas webbing slots. They are bendable for contouring to your back profile. I added the D rings to mount the Bread Bag lid, they will swivel enough for adjustment. Two on each side allow for other accessory attachments. I added a buckle attachment to hold the Bread Bag lid down, based on other Swiss rucks I've worked on. Matching leather side attachments were added by me. Hand-stitching pattern matches other Swiss rucks. Nice stamps from the saddle maker. Leather straps were a little dried out but very vintage, so I didn't replace them. A little Obenauf's made them soft again. With each Swiss ruck I re-do, I send a small block of Swiss wax for "buffleterie" an old French word for leather armor.