I can't remember where I bought it and the maker's label has fallen off. You will see from the photos that each arm is unlocked by way of a cam lever and in 'hinge' there are toothed cups that interlock.
I only 'threw' it on for a demo…….had I been taking it out, I would have put the centre bar lower so it rested where the door handle is and I would have found somewhere underneath (not the bumper) to attach the bottom straps. That way, when the top and bottom are cinched tighter, it is very secure, leaving the side or middle set of straps to lock the whole thing in place.
Have used it three, maybe four times on two different vehicles and found no issue with stability and it didn't damage anything either. This one has retainers for three bikes with a 45kg max weight limit.
Hope this helps with your search……….
I am trying to clear my garage out so if you think it would be suitable, call it £5 (for packaging and fuel) plus postage(no idea how much that would be). It weighs about 3kg, I would say.