Add-A-Rod Curtain Ends.

thingiverse

I created these to enable hanging layered shear curtains on single rod brackets. My wife didn't like how far the typical dual curtain rods hung out from the wall. Single rods of course hang much closer to the wall, but she also wanted to layer shear curtains behind them. There are Add-A-Rods that you can buy for this but they're pricey for what they are and anyway we already had the finial type rods from the dual brackets we previously purchased. These simply slide on to the ends of the rod (19mm outer and 16mm inner) in place of the rod finial.