This is a mount for common sliding shower door handles. We had one break, and weren't able to find at the store to replace it. I've had one installed for 2 years now and it doesn't show any signs of wearing out. 

Printed out of Polymaker Polylite ABS on a Prusa Mini with a .4mm nozzle at .15mm layer height. I recommend at least 4 perimeters, and 7 top/bottom layers for strength. PETG or ABS/ASA are fine materials for this bracket. I wouldn't recommend standard PLA, as a very hot shower might warm it up enough to soften it.