Using the stock spool holder on the back of the P1S, I didn't like how my spools were scraping against the exposed stepper motor mounting hardware. This spacer ring slips into the gap between the spool holder and the housing, locking it in place. It's probably much thicker than it really needs to be, but the first version was functional so I've left it as-is.

Print with the tab side flat on the bed, no support needed.