... light demonstrates the examination precision: ≤±3% (F.S) warning way: Acousto-optic, the vibration warning, the power source undervoltage reports tothe response ... or Pump suction methodConcentration unit: ppm,%VOL,%LEL,mg/m3Acousto-optic alarm : means vibrationWorking temperature - 40 ~ 70 °CWork humidity: 0 ~ 95 ...