Panniers frames - noob query
I know this will seem a stupid question to some, but help me out ...
When I had the Bonnie, I had H&B pannier frames, the ones with the 'square loop' on each side that the pannier locks into. I had assumed that this design was unique to H&B, as all the other pannier/box systems I had seen (probably not many) had had their own dedicated racks. This is the frame I had:
However, I have since seen a lot of bikes with a similar (or identical) rack design, and some were definitely not with H&B boxes. Is this square loop design a kind of universal fitting (other than designs such as the Givi Wingrack, of course), or have I got this wrong?
I haven't got the new bike yet (got to sell the Sprint first) but when I do I plan to have a 3-box system. If the frame I have described can be used with more than one make of box, that would be ideal, as I could use it to keep my soft bags out of the rear wheel for the time being, and add hard boxes or roll-top bags later, and I wouldn't be restricted to one make. Does that make sense?
Any advice welcomed.