The SP-352 is a two-digit planar-gas-discharge
("Panaplex") display by Beckman
(formerly Sperry Information Display Division).
I'm looking for two spare displays, to replace flickering
displays in a Heathkit GC-1005 alarm clock.
The flickering occurs most often when the digit 1
(fewest segments lit) is displayed.
These displays were capable of being driven by another Beckman
product series, either a DD-700 or DD-702 integrated circuit.
You can read more information about them
If anyone has a spare display or two, please
drop me a line.