Mercury light source, 20W low pressure discharge lamps for spectral work. Delivers approximately 100 lux at 20 cm with prominent lines at 434.7, 546.0, 577.0, and 579.1 nm as well as many faint lines.
Digital Luxmeter, economical solution for light measurements in a learning situations, the autoranging feature makes a one-button-and-done instrument, auto power-off conserves battery power, and other functions include MAX, MIN, and HOLD, Requires a 9V battery (not included)