Brass dial head 40mm dia with stainless steel screw 0.5mm oг 0.1mm pitch, head divided in 100 divisions, reading to.001mm or.005mm and registering on vertical scale 10-0-10mm frame with feet of stainless steel on p.c.d. of 46mm Separation approх 40mm.

Comprising a convex lens 38mm diameter x 150mm focal length, mounted in a plastic tube 400 x 50mm diameter, and а double convex lens 50mm diameter 500mm focal length mounted on a tube 400 x 55mm diameter.