Lens Curvature Clock
Features a dual measuring scale for 1.49 and 1.60 index lenses. Measure in 0.25D increments from -20.00 to +20.00D for 1.60 index material and from -18.00 to +18.00 for 1.49 index material.
The S4OPTIK lens clock is easy to use and is designed to last.