Often referred to as the Pharmaceutical PSA pattern, European Pharmacopeia pattern or IMA Reticle (USP 788). 

Normally used on a microscope with 10x objective lens so that the main circle (10mm diameter) equates to 1mm at the stage. 10um and 25um dots and circles give quick reference to these sizes. A 10mm scale in 0.1mm divisions relates to 1mm in 0.01mm at the specimen stage when used with a 10x objective lens. If other objective magnifications are used, request a quote for a special calibration factor. We recommend that the PS8 Micrometer Scale with UKAS certificate of calibration is also purchased to calibrate the G57 reticle and provide measurement traceability for ISO. 

Line Thickness

0.010mm +/-0.003mm

Glass Type and Thickness

Soda Lime 1.5mm thick

Overall Tolerance

+/-0.005mm

Diameter Tolerance

+0/-0.1mm

Divisional Marker Lengths

1.8mm, 1.25mm, 0.75mm

Orientation

Correct reading through glass