... alarm with led light 1. gas alarm(detect gas leak) 2.high performance 3.favourable price 4.IP:20 LPG gas leak detector alarm with led ... by1 ,2 …9. when display 3~9, the STATE LED light red, the alarm give slow Di--Di… sound whendisplaying3,4,5 and ... the concentration reach pre-set alarm level, the LED display A, and the unit alarm, STATELED light red and ALARM LED light.When the concentration is below ...