Indication of the concentration of the measured gas. The body has flanges for wall mounting. Power is supplied from an external source. The nominal supply voltage of the gas alarm is 24 volts. The sensors have a current output in the 4-20 mA standard. Marking of explosion protection 1ExdibIIBT4 + H2X. The sensors measure the concentrations of the following gases: methane, propane, hydrocarbon vapor, methanol, alcohol, formaldehyde, carbon monoxide, carbon dioxide, chlorine, hydrogen, hydrogen sulphide, hydrogen chloride, ammonia, nitrogen oxide, nitrogen dioxide, oxygen, sulfur dioxide. It is recommended to use as part of measuring kits with automatic control systems for gas contamination of A8M or A4M and complete with single-channel A1 or A1M control panels.