The N4 is a neon-filled decadic counting tube produced by the German company DGL Pressler (Deutsche Glimmlampen GmbH), mostly known for their special tubes. It functions in a unidirectional, single-pulse mode, with each of its ten stable cathodes accessible via separate pins. According to its datasheet, the tube is capable of up to 25,000 counts per second, making it exceptionally fast for a neon-filled Dekatron.

This unit’s glass envelope is covered with a silver coating likely intended to reduce light bleeding in from the sides affecting readability. Unlike the tiny pins typically used as cathodes in Dekatrons, the N4 features small plates, which give the discharge a noticeably wider appearance. Images of a transparent version, available here, reveal that the tube’s interior is almost empty, explaining its unusually light weight. A variant of the tube featuring a smaller phenolic base was also produced under the designation N3.

The GC12/4B is a neon-filled counting tube manufactured by ETL in Great Britain, capable of bi-directional operation and up to 4,000 counts per second. It features twelve stable cathodes, unlike the usual ten found in most Dekatrons, allowing it to count in base-12. Four of these cathodes are connected to output pins, enabling them to trigger actions such as advancing another Dekatron when active. Divide-by-12 Dekatrons like the GC12/4B were ideal for timekeeping applications since the division of hours, minutes, and seconds in a day aligns with multiples of twelve.