9 Apparatus for analysing gases; combustion gas analyzers; flue gas analyzers; pressure measuring apparatus; gas flow meters; gas meters; gas testing instruments; electric control devices for heating management; temperature indicators; thermostats; water level indicators; pressure indicators; electrical and electronic control apparatus for heating appliances or systems; control instruments for burners; safety systems and their components for detecting the presence of a flame, checking fan operation and ignition of burners; smoke detectors; sound-proofing headphones; downloadable virtual products in the form of gas and smoke analyzers, gas meters and gas testing instruments, heat regulating devices, pressure indicators, control instruments for heating systems, safety systems for burners and gas appliances, sound-proofing headphones and cabins, heating appliances, burners, heat pumps, oil preheaters, filters for use on-line and in on-line virtual worlds; combustion control devices for heating systems.