Thanks Roger, I did a bit more digging and found a number of places I can get just a few. But it's pretty clear that they are widely used in a number of industires (not just automotive, but hydraulic as Trev said, for water pipes, compressed air etc). That's good info about the high pressure fuel, that is a safety critical application. Also as you say there are variants that have a complete circle.
Here is a good reference point I unearthed, which confirms most of what I expected and also shows how they should be properly installed, thus avoiding this issue Wil mentioned as well:
http://www.zeroclips.com/o_clips.htm
e.g.
Jubilee themselves also do O clips, useful PDF here
http://www.jubileeclips.co.uk/pdfs/Lit% ... 0Clips.pdf
again makes the point that the gap at the ear should not be fully closed (1.5mm gap) as this actually ensures a spring action to provide good clamping. Also addresses removal etc
You can also get them in stainless but don't think anyone does them in black, never mind I can fix that.
My only question now is whether I should get a kit of multiple sizes cos I think I'll be using more of these! Like I said - they are not exactly new, they were used on our Mopars originally, but I never gave them a second thought. Now I have!
