| Model | Risley Rotary Prism  | 
|---|---|
| Prism Range | -20D ~ +20D  | 
| Lens Diameter | 28mm  | 
New type Risley prism set, could change trial lenses as requirement.
Prism ranges: +/- 20 PD with handle.
The prism power is controlled with a convenient knurled rotating knob.
Accurately calibrated dial shows prism diopter selected.
The whole set include:
one Risley prism
one Penlight
one Red Maddox Rod Lens
one Clear Maddox Rod Lens
one Black Leather Case