SPECIFICATIONSphere:                 -29.00D to +26.75D step (0.12D/0.25D/0.50D/1.00D/3.00D) Cylinder:               -8.75D to +8.75Dstep (0.25D/0.50D/1.00D/3.00D)Cylinder axis:           0 to180�  Step (1� / 5�/15�)Rotary Prism:           -20 to +20   step (0.1 / 0.5 / 1)Prism Form:             Base up, base down, base in, base outNear Distance:     Mechanical converging with an optical axis at 40 to 67 in front of eyeBinocular Balance:       Rotary Prism, polarizing filter and R & G filterCross Cylinder Lens:     +/-0.50DCorneal alignment:       12 to 20m