Measuring range: 99.9/999/9,990/99,900/999,000 lx.
Accuracy: ±(4% rdg+1 dgt)
Features: Timer hold, Deviation display and Automatic power-off function

Measuring range: 9.99/99.9/999/9,990/99,900/999,000 lx
Accuracy: ±(2% rdg+1 dgt)
Features: In addition to the 51001's function: Ripple measurement, Average illuminance computation.

Measuring range: 300/1,000/3,000 lx
Accuracy: ±7% rdg
Features: 3 ranges, Output to recorder

Measuring range: 3/10/30/100/300 lx
Accuracy: ±7% rdg
Features: 5 ranges, Output to recorder