Bacharach MGS-450 Gas Detector Transmitter with semiconductor sensor for Refrigerant Gases (HFC, CFC, HCFC) 0-1000ppm measurement in Refrigeration Applications. 3 x relays (low, high & fault), analog output (4 to 20 mA, 0 to 5 V, 0 to 10 V, 1 to 5 V, 2 to 10 V), RS485 MODBUS RTU output, included audible & visual alarms: 72dB @10cm buzzer and single tri-color LED (green, red, orange). IP41 or IP66 Housing. CE, UL and CSA Approvals. Factory configured for either R134A, R404A, R407A, R410A, R22, R507A, R407C, R407f, R-1234ze, R32, R448A, R452A, R513A, R434A, R450A, R1234yf, R514A, R452B, R454A, R422, R422D, R427A, R449A or R454C. Mobile App Bluetooth Interface.