Whipped up a quick set of gauge blocks for laser focusing, they are pretty accurate, and work well ..

Created two versions of the blocks and holder, one is small (10mm diameter on the blocks) the other is large, (20mm diameter on the blocks).

Voxelab Aries

Doesn't Matter

No

.1

15%

Pretty accurate, may have to tweak the settings for better resolution on your particular printer.

On my printer these all printed just a touch oversized, just a couple swipes with some sandpaper and they were right on the money ..