Thorlabs S175C microscope slide power meter. Thermopile type.

Work correctly with PM100D. Will need calibration, as it expired 9/2020.

Seems to respond correctly, when compared to other Power meters.

Seems to have directed with a sharply focus laser and inscribed a tiny bit.

The photos are taken in reflection with high illumination to show the detail of what is under the glass.

Glass is not scratched.