... detector with lcd display and alarm Technical features:1) 4-20mA, 3 wire connection ,compatible with existing alarm control unit ... Play! .5) Sensor replacement without recalibration, automatic sensor data recognition. Sensor fault signal output monitoring and indicating.6) Programmable ... main display 8-digit 14-segment additional display 52 bars meter with 2% resolution10) Unit: ppm, mA, %,%LEL%VOL11 ...