These are unusual.  If you have hanging curtains on a single rod, traverse or other, one can hook this liner up behind a curtain or before hanging an outer curtain on the same rod you have your outer curtain on, because the hangers on this liner open and shut and can be installed between curtain hooks. Since we don’t open these curtains, this liner solved the problem of tv glare through existing curtains. I don’t like to admit taking this short cut, but we were saved buying and installing new double traverse rods and perhaps new curtains. The old curtains we had had custom made, so I didn’t want to give them up. So I had them dry cleaned, and this curtain liner was our problem solver.  For a standard traverse or round rod for grommet curtains, I wouldn’t recommend these as a first choice.