The GX-3R Pro is the world’s smallest 5 gas monitor weighing only 129 grams and fits in the palm of your hand (73 W x 65 H x 26 D mm). It simultaneously monitors and displays 5 different gases. In addition to monitoring standard confined space gases, LEL, O2, CO, & H2S, the GX3R Pro has a 5th channel where you can add infrared or toxic gas sensors.Two of the four sensor slots have interchangeable sensors providing flexible configurations, which can easily be changed in the field.