Product Features Full Aperture Lenses Minus Cylinder Wood Storage Case S4OPTIK Perimeter Full Aperture Trial Lens Set with Wooden Case – Minus Cylinder Only. Includes the following clearly marked lenses: Spherical Lenses ±0.25 to ± 3.00D in 0.25D steps ± 3.50 to ± 7.00D in 0.50D steps ±8.00 to ±14.00 in 1.00D steps 16.00D Minus Cylinder Lenses -0.25 to -1.00D in 0.25D steps -1.50 to -5.00D in 0.50D steps