General Tool PNG2000A Natural Gas Detector Pen Audible and visible annunciation LED indicates; green on, yellow indicates 200-Ppm, red indicates 500-Ppm Catalytic combustion sensor Per calibrated Compact and lightweight Ideal for HVAC, household etc. • Audible and visible annunciation • LEDS: green, on; yellow, 500 ppm; red 200ppm • Detects lng, lpg, ch4, methane, butane, [...]