I have one PBSF attached to my saddle above my seat bag, I just wrapped 1" wide double sided velcro strips around the saddle post, then have a single 6" long velcro strip that the PBSF is clipped too. It's not pretty, but it works, can be angled correctly, and is quick to pull off if I need to lock the bike in public. I'm sure there are much more elegant ways to attach it...