Specification:
| Model | CL-21 | CL-23 | CL-22 | CL-24 |
| Screen Size | 21.5 inch | 23 inch | 22 inch | 24 inch |
| Working distance | 1m-6.5m | |||
| Remote control distance | 0-8m | |||
| Power supply | AC100V to 240V, 50/60Hz | |||
| Power | 48W | |||
| Vision recording methods | Decimal & Imperial fraction | |||
| Optotypes | Tumbling E, Landolt C and Alphabet etc | |||
| Test Graph | ETDRS, Contrast Sensitity Test, Contrast Test, Ishihara, Cross Cylinder, Astigmatic Fan Dial, Cross Grid, Fixation Spot Test, Stereo Test, Red/Green Test, Worth Four-Dot Test, ect | |||