Higher magnification calibration slide

[Notinuse]

Calibration slides are used in microscope work to measure.
Example; https://amscope.co.uk/products/0-01mm-microscope-calibration-slide
It shows 1 mm with 100 dividing lines; 0.01mm or 10 micrometers.
This works great for magnifications up to, say 250x
Beyond this the lines start to look quite chunky.

I need a calibration slide with finer lines, to use for higher magnifications.
Any recommendations? (TIA)

 

[tech99]

I thought the graticule was placed in the eyepiece so is not subject to the full magnification?

 

[berkeman]

@Andrew Mason