M&N AC220v Vehicle Emission Gas Analyzer Tail Gas Analyzer Co / Hc Emissions Exhaust Gas Emissions Analyzer Equipment 1, measuring range: 0 --- 25% 2, the measurement accuracy:  1% 3, the working environment temperature: 0 ~ 45 4, relative humidity: 85% 5, Response time: 15S 6, the working voltage: AC220V It is not tester, but a Analyzer to determine theautomobile exhaust carbon monoxide (CO)And hydrocarbons (HC)Emissions according the oxygen