ZABBYS WELCH ALLYN SPOT SCREENER 
Product Specifications 
Dimensions 8.5 in. x 6.75 in. x 4.75 in. (20.3 cm x 15.2 cm x 10.2 cm) 
Weight ~2.55 lbs. (1157 g) 
Wireless Network 802.11 b/g/n 
Operating Temperatures 50 °F to 104 °F (+10 °C to +40 °C) 
Operating Humidity 30% to 95% relative humidity (non-condensing) 
Storage/Shipping Temperatures 32 °F to 122 °F (0 °C to +50 °C) 
Storage/Shipping Humidity 0% to 95% relative humidity (non-condensing) 
Storage/Shipping Atmospheric Pressure 800 hPA to 1060 hPA 
Expected Battery Life 2.5 years (under normal usage) 

Measurement


Spherical Equivalent Range: -7.50D to +7.50D in 0.25D increments 
Accuracy: -3.50D to 3.50D, ± 0.50D -7.50D to < -3.50D, ± 1.00D > 3.50D to 6.00D, ± 1.00D 
Cylindrical Range: 0.00D to +3.00D in 0.25D increments 
Accuracy: 0.00D to 1.50D, ± 0.50D 
> 1.50D to 3.00D, ± 1.00D 
Cylindrical Axis Range:: 1 to 180 degrees in 1-degree increments 
Accuracy: ± 5 degrees (for cylinder values > 0.5D) 
Pupil Size Range: 4.0 mm to 9.0 mm in 0.1 mm increments 
Accuracy: ± 0.1 mm 
Pupil Distance Range: 35 mm to 80 mm in 1 mm increments 
Accuracy: ± 1 mm 
Gaze Measurement 0 to 20 degrees in increments of 1-degree nasal, temporal, inferior, and superior 
Accuracy: 0 to 5 degrees (± 1 degree) > 5 to 20 degrees (± 2 degrees) 
Time Per Measurement 1 second 
Measuring Distance 3.3 ft. ± 2 in. (1 m ± 5 cm) 
Fixation Target Random visual pattern and audible sound 
Measurement Principal Optical reflex