This thing is a replacement part for a trash bag holder I have from a famous garden brand whose items are usually grey and/or orange.
I lost one that probably fell in the bag and was thrown away so I designed and printed this replacement part.
It's a simple clip that will fit any 20mm diameter tube.
Print it using ABS with something like 30 or 50% infill and just one shell.
You may then clip it on any 20mm diameter tube.