The 1420 held down the baseline of Sears amplifiers into the early 70s. It was the lowest powered, the smallest speaker, but still held on the little bit of cool of a tube-powered amplifier. It looked very similar to the first 'tombstone,' the 1459.
Spring/Summer 1968 at $27.95
as the 57K1420L
Sears trotted out the 1420 number as the prefix for its low end amps well into the 1980s!