My toilet flush arm broke and instead of trying to buy one I decided to design in OnShape and 3D printed one. Sorry, I don't know the manufacture but the ones I found on line did not look like my flush arm. Some wanted to replace the entire assembly, some had a triangular hole.

Mine has a square mount hole that is slightly tapered, The old arm had stiffening sides that extruded past the main part. I added the stiffening sides but only up one side. This allowed the print to be flat on the build table.

The arm is 219.5 mm (8.6 in) long.

Build Settings:

0.2mm layer height

4 walls

Support: I don't think it was needed but I printed in PLA and used PETG as regular support interface. No brim.

I saved the uploaded the files in STL, STEP and 3MF

I hope someone finds this useful.