... 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 light1. gas ... changing by1 ,2 …9. when display 3~9, the STATE LED light red, the alarm give slow Di--Di… sound whendisplaying3,4 ... pre-set alarm level, the LED display A, and the unit alarm, STATELED light red and ALARM LED light.When the concentration is below ...