Meets the most recent UL 1484 standard, built-in the high sensitivity, the high stability and the high gas selectivity's characteristic may precise detect the LPG/ LNG. With the advanced high tech microprocessor and the wisdom control, processing the precise computation of the LPG /LNG concentration and through time, and have much intelligent control. Item No. LK-680N Gas Alarm 1. Meets the most recent UL 1484 standard 2. Built-in the high tech gas sensor, i t has the high sensitivity, the high stability, and the high gas selectivity’s characteristic, may precise detect the LPG/ LNG. 3. With the advanced high tech microprocessor and the wisdom control, processing the precise computation of the LPG/ LNG concentration and through time, and have much intelligent control. 4. Built-in the high efficiency wide-range Switching Power Supply, suitable to the universal voltage.