1. Please check the mounting hole size to make sure this shower arm fits.
You could consult your professional contractors about installation.
2. Heavy-Duty Solid Brass material for both shower arm and escutcheon / flange.
This 12 inch round ceiling mount shower arm is made of diameter 15/16 inch solid brass pipe.
Flange size is Diameter 2.36 inch X 0.4 inch.
3. Both sides are Soldered 1/2 NPT Tapered Threads.
Need indication for choosing a high quality shower arm? How to Choose a High Quality Shower Arm