TS21I-CAT-H2 gas detector is suitable for Hydrogen gas. Application area of this detector is Refineries, Chemical plant, Gas Cylinder Refilling and Battery Back Power Stations etc where gas leakage is possible. It reads the gas con-centration in Air and transmits to a detection panel over digital bus as well as it is show LEL level on display. Catalytic type of gas sensor is used in this de-tector , This sensor is provide good reproducibility, good performance against changes in atmospheric temperature and humidity. It has long lifespan and easy operation. Detector have provision to set Two alarm levels of warnings (High & Low).