The GX-3R Pro is the world’s smallest 5-gas monitor weighing 4.58 ounces and fits in the palm of your hand. It simultaneously monitors and displays 5 different gases. In addition to monitoring standard confined space gases, LEL, O2, CO, & H2S, the GX-3R Pro has a 5th channel where you can add infrared or toxic gas sensors and Nitrogen Dioxide (NO2) sensors. Two of the four sensor slots have interchangeable sensors providing flexible configurations, which can easily be changed in the field.