Echnical specifications of the trial set: total 225 lenses lenses 0.12 to 20sph +- one pair each 0.12 to 06cyl +- one pair each 10 prisms upto 12. 07 standard access. (2 blanks, pinhole, slit, red, green & maddox rod) size 0.12 to 6.00 dioptors 25mm reduced aperture lenses 7.00 to 20 dioptors 20mm reduced aperture lenses