bentax1978
4 of a Kind
"B" is a "bit" larger than a med flate rate box
I end up using a fair number of regional A and B boxes at work since we ship a lot of heavy (relative to their volume) items to locations that are generally within a zone of where we ship from. I very seldom use medium flat rate boxes unless I'm sending something a longer distance.
There's also a B2 regional box which has a larger footprint than the B1, but is not as tall (similar to the "board game" box, but small). It's about 10% larger by volume than a B1 box, but I can't say I've ever thought about how I'd best pack chips in it.
B1
B2