Gas detector DTN26
They have luminous indicators and very loud sound buzzer.
They can drive any kind of safety valve (NO/NC) and they can be supplied with 12VDC or 230VAC. Stand alone and network operation are both possible. Thus bigger buildings can be monitored with the same equipment.
At the time interval that is predetermined by the national regulations only the sensing element should be replaced, instead of the whole detector.
They are fully certified for safety, electromagnetic compatibility as well as for their correct functionality according to the newer directives EN50194/00 and prEN50194/05.