Multi-gas detectors can detect the presence of multiple gases at the same time, instead of just one. Most detectors of this type have between 2 to 6 gas sensors. So instead of owning a CO2 detector, a natural gas detector, or another selective gas detector, you’ll only need one unit. These units come in all shapes, sizes, and functionalities.. Zoro has a wide selection of fixed gas detectors and other types of calibration equipment. And if your existing gas detector is on the fritz, we have gas detection accessories and replacement sensors to get it back online fast. And don’t forget about multi-gas protector cases too.