I miss the old "bayonet lock" ones, like on this page - they don't make them anymore. The special thing about them was they were "bistable" in both the locked a

I miss the old "bayonet lock" ones, like on this page - they don't make them anymore. The special thing about them was they were "bistable" in both the locked and the unlocked positions, whereas twistlocks these days automatically go into the locked position if you let go of them. For the obvious counter-argument, that you can forget to lock them: that's true of screw gates as well, and yet we still use them.