Description :  KERUI GD23 TFT Wireless Human Voice Prompt Hybrid Gas Detector Alarm with Black Box Recording 433MHz   Features :  TFT color display、 easy to use. Human voice prompt、 English and Chinese for optional. Highly reliability catalytic combustion sensor. With black box to facilitate alarm for historical record.   Display gas concentration(PPM).   Can set highest and lowest alarm value by yourself.   Microprocessor intelligent control.      It supports 433MHz wireless alarm system.      Specification :    Operating voltage: AC100V-240V   Built-in 3.7V rechargeable lithium battery.   Wireless frequency: 433MHz   Signal transmission distance: 100 m   Operating temperature: -20 \u2103 to 50 \u2103     Package includeds :  1 x KERUI GD23 Hybrid Gas Detector   Details pictures :