Counting Reticles
KR-803 Merz
| KR-801A | 6MM Base length | |
| KR-801B | 6.4MM Base length | |
| KR-801C | 4.5MM Base length | |
| KR-801D | 4.8MM Base length | |
| KR-801E | 8.4MM Base length |
The circle area of the porton reticle increase with root 2 progression as do the dividings on the right hand side of the rectangle. These dividings are numbered for convenience. The specimen is racked on the mechanical stage of the microscope and traverses are taken right across the deposit sizing all the particles encountered.

