1. Digital regulators, constant temperature regulators, room temperature regulators, heating regulators, flue gas thermostats, submergible thermostats, pipe laying thermostats, regulating thermostats, temperature regulators, radio controls, smoke and heat alarms, thermometers, digital indicators, electric chimney draught regulators, control apparatus for burners, phototubes, checkers, spark electrodes, double spark electrodes, ionisation electrodes, manometers, electric individual room regulators, solar regulators