Good Commuter Bag with a few Shortcomings
I'm using this bag on a converted 80s mtb I commute to work on. It is attached to a Brooks B67 by the bag loops, and I use metal zipties through the bag loops and also from the underside to the saddle rails for security. I'm obviously not planning to use the shoulder strap feature (not advertised?) but to leave the bag on the bike at my workplace bike rack. Fingers crossed that it won't get stolen! I won't leave anything valuable in the bag, as there is no provision for security on the pockets or main area.
The size is good for a few tools and tubes on the side pockets, and a lunch, a sweater, and a few books in the main compartment. You could probably get a small laptop or ipad in there as well, but I haven't tried.
The strap that is suppose to connect the bottom/rear of the bag with the seatpost is far too short to be useful, so I don't use that. With the limited loads I put in, the bag is plenty stable with just the bagloop connections.
I do wish there was a loop of some kind to hang a rear blinky light. The bag itself covers the seatpost light I was using previously. I've got a magnetic-hold light on there now, but I worry that it will fall off. This would be a minor addition of great utility!
The bag does look great in that retro Brooks way!