Assembled, hand built, moulded, cast. Polished, engraved. Surface finish: polished.
Inscriptions & markings
Damaged label adhered to upper face: “PUR[illegible] BY/ UN[illegible]” Metal plate: “AUDIO OSCILLATOR/TYPE 813A SERIAL NO. 6. [the number 6 is inscribed into the surface]/ GENERAL RADIO CO./CAMBRIDGE, MASS. U.S.A./ OFF [2 arrows] ON”
