Once you've cleaned up your dog mess you don't have to hold the poop bag in your hand for the rest of his walk.
This handy clip fits onto the handle of the dog's retractable lead which enables a cheap (Lidl / Aldi) carabiner, or one of the many wonderful carabiners available on Thingiverse, to be attached to it. The poop bag is simply clipped onto it and the walk continues until you find a handy dog poop bin to dispose of it.
This is very useful when you are walking several dogs and there isn't a poop bin at hand for quite some while.
I've also attached the .STP file so you can modify the design with your own preferred design software.
0.28mm layer (0.4mm nozzle)
BALCO (Aldi) PLA
Only takes 12 minutes to print and costs 2p to make.
I have printed various carabiners - not just for this project - and find that PETG is the best filament to use due to its combination of strength & flexibility