Replacement Washer for Glockenspiel (Bells/Xylophone) Bars that have missing/broken washers. Easy to fix and replace. Designed for a Musser glock, but should be compatible with most brands.
Pxmalion Flexible PLA
Flexible filament is a closer material to the original, and won't wear down the bars as much.
To save time when printing many, print so that the base is the larger end. The countersink will be less pronounced and the screw will thus be slightly prouder, but that really doesn't matter when installed.
If you only need one, and don't mind removing stubborn supports, print upside down with supports for a better countersink. The benefits are negligible in my opinion.