I have tried many shoulder bags in the past few years and none have been satisfactory. Too small, too big, I feel like Goldilocks sometimes. While at a local gun show I noticed the Finn gas mask bag for $7. I have messed with them in the past but never gave them much thought. For $7 why not. I honestly was going to use it for a tool bag or range/ammo bag. Started messing with it and discovered it can hold a days kit easily and with style. I had the leather shoulder pad strap from a buddy and it fit perfectly.
Updated: I used this bag for many day trips and also for around camp as a catch all bag. For the money you can't beat it. I think online they are selling for more then I paid. I prefer the version that is compartmentalized, it gives you a nice area to store a water bottle or canteen. This bag is ripe for customizing and could use a better and wider shoulder strap.