For 22mm diameter shower pole. 22mm is just shy of 7/8 inch iirc. 0.86614 Inches according to google for my Imperial friends.

Just a quick shower basket/shower shelf I made to fit the small amount of clearance I have between the shower rod and the wall behind, that I also think looks pretty good in black.

Threads are metric M6.

I made this with PETG so the screw is plenty strong enough, but if you have a metal M6x8mm hex head you'd wanna use instead go ahead with that.

Can increase infill/wall count for the screw to increase its strength. I just upped wall count on the screw to 7 to make it completely solid.