LM-S1
                                 SPECIFICATIONS
  Type 

 Direct scale reading

  Target  Corona target
  Vertex Power Scale  0 to ±20 diopters ; 0.25D graduations
  Prism Diopter Scale  0 to 5 prism diopters ; 1 graduations 
  Protracter Scale        0 to 180 degrees ; 2.5° graduations
  Lens Diameter  30 to 90 mm Ø
  Eyepiece Adjustment  +3 to -5 diopters (approx.)
  Instrument Tilt  0 to 90 degrees, freely adjustable
  Light Source  LED
  Power Source  Two 1.5V AA batteries (Also, usable with two Ni-Cd 1.2V  

 batteries )
  Operating Time 

 150 hours (approx.) (when used continuously)
  Auto Shut-off  2.5 minutes
  Weight  3 kg.
  Dimensions  285 (H) x 140 (W) x 370 (D) mm (when tilted to 30°)