The GR10G (also known as CV8090) is a large Nixie tube produced by the British manufacturer ETL. It stands out due to its unconventional design: notably, it lacks a solid back plate on the anode cage, allowing the digits to be viewed clearly even from behind the tube.

Its unusual characteristics extend to its electrical specifications. According to the datasheet, the recommended supply voltage is at least 220V, with an internal voltage drop of approximately 180V across the ionizing tube. Furthermore, the recommended minimum operating current of 6mA is higher than typical for Nixie tubes of similar size. Its gas mixture does not appear to contain mercury vapor, which likely contributes to its poor average lifespan rating of only 5000 hours. This short lifespan restricts its practical use in many projects, despite its distinctive visual appeal.

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.

The GR10H is an early Nixie tube produced by ETL, featuring digits visible through a small viewing window, with the majority of its envelope coated in black paint—likely intended to enhance contrast and minimize light bleed from adjacent tubes. Shown at the end of this page is a transparent GR10H revealing that, like in the STC GN-1, the digits are connected to the tube’s pins via thick wires and an evaporative getter was used.