I also have multiple saddle bags for the same reasons as
Koyote, 4 that I use regularly.
For small ones, I have an Orucase and the Lezyne that I like. I think the Lezyne is the "road caddy", and looks like the ALMSTHRE. The securing mechanism is pretty solid (wide nylon straps with a plastic loop and velcro attachment). I actually use it on my MTB with no issue.