Foolestroupe -

The thin rubber strap that clips into a handle is the "strap wrench" I mentioned earlier. I keep two in the kitchen drawer so I can put one on the lid and another on the jar for the really stuborn ones.

Most of the easily available ones now have a "looks like rubber but it's really plastic" strap that's often too stiff to be adjusted one-handed. With little searching about, it may be possible to find one of the older style with a woven cloth (like an old fashioned lamp wick) strap, but nearly all with that feature have a cast iron handle, and may be $30 (US) instead of $1.50.

I have one of the "rubber strap" ones with a little "release button" on the handle that makes it a lot easier to get the right adjustment, but that also almost requires both hands to make the adjustment since you have tohold the button while you slide the strap to the right length.

John