Special equipment for measuring refraction deflection and astigmatism axis.
conventient to use rotated 360 degree upward and downward.
working distance: 1m (or according to artifical short sight distance)
Adjustable range of streak: 3mm - 20mm
Streak Rotation: 360 degree
Illumiation source: 3v/2.1w halogen bulb
Power: AC 220V/50Hz 110V/60Hz