Sound amplifier installations either for personal use, or for use in public establishments, such as churches, cinema theatres and theatres as an aid for persons hard of hearing; apparatus, installations and devices for the measuring and testing of hearing; apparatus, installations and devices for collective and individual teaching of hearing and speech to persons hard of hearing, to deaf-and-dumb and to persons generally of subnormal standard; apparatus, installations and devices for environmental acoustic correction and for individual protection; audiometric cabins, soundproof chambers, anechoic chambers, with or without electric or electro-magnetic screens, installations for behavioural research

Electro-acoustic appliances and apparatus, with or without batteries, for use by persons hard of hearing; parts and replacement parts of such appliances and apparatus including: air conduction receivers and transducers, bone conduction receivers and transducers, ear adapters for air conduction receivers and transducers, earphone holders, connectors for interconnecting receivers and amplifiers, miniature plugs, adapters for independant batteries with connections and cables for use between amflifiers and batteries; accessories, such as feeders for networks, inductance devices for general use with telephones, and any other devices for connection to or separate from the appliance or apparatus for improving the aid given to persons hard of hearing; sound amplifier installations either for personal use; or for use in public establishments, such as churches, cinema theatres and Theatres as an aid for persons hard of hearing apparatus, installations and devices for the measuring and testing of hearing; apparatus, installations and devices for collective and individual teaching of hearing and speech to persons hard or hearing, to deaf-and dumb and to persons generally of subnormal standard; apparatus, installations and devices for environmental scoustic correction and for individual protection; audiometric cabins, soundproof chambers, anechoic chambers, with or without electric or electro-magnetic screens, installations for behavioural research