Whether you’re protecting general workers or responders in industries includingpetrochemical, steel, or utilities, the Honeywell BW™ Flex Series delivers what youneed in an easy to use serviceable package. Sensor 1: %LEL (combustibles), catalytic, filtered Sensor 2: None (dummy sensor) Sensor 3: H2S (hydrogen sulfide) inflow Sensor 4: NO (nitrogen oxide) Housing: Yellow housing Region: Japan