12

Common type USA tube/semicond. Airhawk - tubes Airtron, H. & H. Radio Co.; Newark, NJ Amplitron = Tube brand Apex, Radio Tube Corporation; Newark, NJ Belltone = Tube brand Clearatone (tubes), Radio Tube Laboratory; New York City, NY Gold Bond (tube brand) Rolls Royce Tube Co.; Newark, NJ Silvertron, New York Radio Co; New York, NY Sonora Tube Co.; Chicago, IL Speed, Cable Radio Tube Corp. / Cable Supply Co.; New York and Brooklyn, NY