The Guardian is a newly expanded family of wall mounted, continuous gas monitors available for carbon monoxide, hydrogen sulfide, oxygen, chlorine, sulfur dioxide, hydrogen cyanide, hydrogen chloride, nitrogen dioxide, nitric oxide, hydrogen and many others. Standard features include digital display, NEMA 4X enclosures, output relays, and multi-level audio and visual alarms. CEA Instruments' Guardian controller is available with up to four remote sensors which are fast responding and unaffected by temperature and humidity changes. A system test button, local danger alarm indicator and fault alarm assures proper operations. The unit is easy to install, operate and maintain.