Sphero Meters
Product Details:

Scale	10-0-10 mm
Rass Disc	100 Divisions.
Pitch	1 mm
Least Count	0.1 mm.

Spherometers are used for accurate measurement of the radius of curvature of spherical lenses. Three-pronged brass table with three pointed legs carries a vertical main scale from 10-0-10 mm on one of the prongs, and a micrometer scale on a brass disc with 100 divisions. The table has a screw at its center with a pitch of 1 mm. Giving a least count of 0.1 mm.