Scale reticle, for use with 3X objective. Dual vertical scales - 4mm/200 div. and 0.150in/150 div.
On this type of scale the dimensions shown represent the microscope's stage rather than being the actual dimensions on the reticle itself. The actual (1x) scale sizes on the reticle are 12mm and 0.450in. but are labeled 1/3rd these numbers for ease of use with a 3x objective.