Display: two groups of four LED display; 
 Display Mode: ppm or mv; 
 Display Resolution: three significant digits; 
 Range :0.1-10000ppm or-500mv - 500mv; 
 0-5V output signal; 
 Stability: Drift less than or equal to 1 week, numbers; 
 Power supply: 220V, 50Hz AC, power consumption is about 3 W;