... durable 3) fast calibration device Product Name: (CO,H2S,O2,LEL) portable impact pro M40 with pump M40 SPECIFICATIONS: Size: 4. ... Custom Graphic LCD with Backlight SENSOR SPECIFICATIONS: GasRangeResolutionT90Carbon Monoxide(CO)0~999ppm1ppm48secHydrogen Sulfide(H2S)0~500ppm1ppm30secOxygen(O2)0~30%0 ... or problems, please feel free to contact me. Thanks. (CO,H2S,O2,LEL) portable impact pro M40 with pump