The 12BZ7 is a high-μ double triode. The primary design purpose is as a sync separator and sync amplifier in television receivers. A secondary use would be as a general purpose audio amplifier.
The twin triodes and the CBS brand on the envelope.
The stitched anode and Made in USA.
The 59-480 looks to be a part number. The original identification is etched with the CBS information overprinted.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
Reference: Data-sheet. Type 12BZ7 was first introduced in 1952. See also1952 adverts.
