4-digit LCD display the best measurement of the spectral response ≦ 6% automatic transmission function from the accurate and quick response of 0.05 to 7000 lumens reading lock data memory and read function to zero the function of the ratio of the value of functional classification selection function of the photopic function : light emitting diode, light bulb, fiber optic lighting, automatic shutdown feature RS232 interface using a simple test baffle: 2/3/4/5/8/10m/m