Nikon M Plan Booster 10X for Nikon V-12 Optical Comparator. 3-position turret with RMS thread. 

In good working condition with obvious signs of wear and age as pictured. Optics are in good condition, no scratches, haze, fungus or delamination. Some micro dust particles and small cleaning marks which will have no effect on image quality. Turret is turning smoothly.