The ZM1040 is a large Nixie tube produced by various European manufacturers, with this particular unit made by Valvo. Tesla, a Czechoslovakian manufacturer, produced a version of the ZM1040 that featured a square anode grid, setting it apart from the one shown here. To enhance contrast and filter out blue light emitted by the included mercury vapor, the tube is covered with a red filter. A variant without this filter was also available under the designation ZM1042.

The DGM01 is a modern Nixie tube produced by Sadudu and his company iNixie LAB in China, comparable in size to the Soviet IN-18. Like the R|Z568M by Dalibor Farný, the DGM01 is assembled by hand in small quantities. Each digit in the tube has a distinctive design, with the numbers one and five standing out in particular. Notably, the DGM01 features a right decimal point which is unusual for tubes of this size and was specifically incorporated for use in replicas of the Divergence Meter from the popular anime series Steins;Gate. Unlike the R|Z568M and tubes made by Millclock, which have a large metal bases, the DGM01 utilizes proper pin-to-glass seals, enhancing its authentic appearance. The glow discharge exhibits the characteristic blue tint seen in tubes containing mercury vapor, which is indicative of long-life Nixie tubes.

The CD66A, produced by NEC in Japan, is a medium-sized Nixie tube capable of displaying all ten digits along with a right decimal point. It features a distinctive anode design made up of multiple horizontal wires, differing from the typical hexagonal or square grids stamped from sheet metal in most Nixie tubes. A variant of the CD66 with a left decimal point was also available. Additionally, the CD66A is pin-compatible with the European ZM1242, which has a more conventional design.

The XN1 is an early Nixie tube produced by Hivac in Great Britain and Lorenz in Germany. The earliest documentation referencing this tube I could find is dated September 9, 1961, shortly after the invention of Nixie tubes. This particular unit features an evaporative getter at the top, giving it a distinctive appearance typically associated with vacuum tubes (often seen in VFDs). However, versions with a getter located behind the anode cage were also manufactured. The tube’s anode cage is notably restrictive, limiting visibility to mostly straight-on angles. Unlike many other tubes of similar size, the XN1 does not include any decimal points.

With its 40mm digits, the IN-18 (“NH-18”) is the largest Nixie tube mass-manufactured in the Soviet Union. It shares the same envelope diameter with smaller Nixie tubes, such as the ZM1040 and Z566M, which gives the IN-18’s digits a slightly elongated appearance. Today, the IN-18 is among the most popular Nixie tubes, often used in large Nixie clocks. Although vast quantities were manufactured and remain readily available on online marketplaces like eBay, IN-18 tubes have become quite expensive. Unlike many Soviet Nixie tubes, the IN-18 features a proper cathode for the number five rather than an inverted two. Its gas mixture includes trace amounts of mercury vapor, which significantly extends the tube’s lifespan and imparts a faint bluish tint to its glow.

The IN-1 (“NH-1”) is the first generation of Nixie tube mass-produced in the Soviet Union by Anod. Like many other Soviet Nixie tubes, the IN-1 utilizes an inverted two to represent the number five, although at least some earlier models featured a proper five. This tube is notable for its large phenolic base, with each pin conveniently numbered. As is typical of early Nixie tube designs, the IN-1’s gas mixture lacks mercury vapor, which results in reduced longevity. It is, however, pin-compatible with and visually very similar to the Dolam LC-516, which could be considered as a longer-lasting alternative for those who appreciate the IN-1’s UFO-like design. Original U11 sockets are notoriously difficult to come by so building a device using either of them would likely require coming up with a custom made socket design.

The GN-2 is a large Nixie tube produced by STC as part of their ‘Nodistron’ line of display tubes. It is pin-compatible with and the direct successor to the GN-1 and already shows notable advancements in Nixie tube manufacturing. Unlike its predecessor, the GN-2 features digits stamped from sheet metal instead of ones made from bent wire. These digits are arranged in a more compact stack, separated by insulating rings. The thick wires previously used to connect the numerals to their corresponding pins have been replaced with the thinner leads seen in most later top-viewing Nixie tubes. Additionally, the GN-2 no longer employs evaporative getters and the pin connected to the anode meant for operation with rectified AC voltage on the GN-1 is now marked as NC in the tube’s datasheet. The tube’s numerals emit the same distinctive orange glow seen in the GN-1, indicative of a mercury-free production process suggesting a relatively short operational lifespan.

The GR-211 is a large Nixie tube produced by Rodan-Okaya in Japan. It ranks as the third-largest Nixie tube made by Rodan and succeeded the short-lived GR-11. Later models were rebranded as CD94. Notably, the GR-211 includes a left decimal point, which is uncommon for tubes of its size. In devices using larger Nixie tubes, a separate neon bulb typically represented the comma instead. Interestingly, the datasheet marks the decimal point’s pin as “not connected.”

The R|Z568M is a massive modern Nixie tube produced by Dalibor Farný and his company. Each tube is manufactured by hand in the Czech Republic. As the name suggests, its design is meant to be reminiscent of the Z568M, the largest Nixie tube produced in the GDR. A picture below shows a comparison between the R|Z568M, an original Z568M, and a Z566M. Despite being the smallest of the three, the Z566M, with its 30mm digit height, is still considered a large tube. This makes the impressive scale of the R|Z568M, featuring 50mm digits, even more striking. The manufacturing process of an R|Z568M tube is documented in this video.

The Z566M is a large Nixie tube manufactured by RFT. It is pin compatible with the ZM1040 but differs in design, featuring a flatter top and a top-evacuation design, though some earlier units were evacuated from the bottom. In some instances, Z566Ms have even been rebranded and sold as ZM1040s (see picture at the end of this page). A variant without the pre-applied red filter was marketed as the Z5660M.

The Z566M was primarily utilized in laboratory equipment such as voltmeters and frequency counters. Its large size also made it well-suited for devices designed for use in educational settings, such as schools. A Nixie tube featuring various symbols, designed to complement the Z566M/Z5660M, was marketed under the names Z567M and Z5670M.

The LC-516, produced by Polish tube manufacturer Dolam (later known as Unitra Dolam), is pin-compatible with and visually similar to the Soviet IN-1 Nixie tube. However, unlike the IN-1—an early model with a relatively short lifespan—the LC-516 is mercury-doped, significantly enhancing its durability and giving its glow a subtle bluish tint. The LC-516 features a slightly smaller glass envelope and digits compared to the IN-1; a comparison between the two is shown below. Additionally, Dolam manufactured a version without the phenolic base, designated as the LC-513.

The National Union GI-10 is likely the first Nixie tube ever produced, belonging to National Union’s Inditron series of display tubes. Patented applied for in 1954 (and granted in 1956), it predates the original “NIXI” tube developed by Haydu Brothers and later Burroughs by at least a few months. Similar to other early Nixie tubes, such as the STC GN-1, its digits are not stamped from sheet metal but are crafted from wire. These digits are connected to the tube’s 10 pins via long rods covered in an insulating layer of ceramic that also serve to hold them in place. In contrast to more modern Nixie tubes, where the digits are arranged to minimize obstruction of each other, the digits in the GI-10 are organized in a straightforward, sequential manner. The zero digit is positioned at the very front, while the one is located at the farthest point in the stack. Unlike most later Nixie designs, the GI-10 lacks a dedicated anode; instead, activating a specific digit requires all other electrodes to be held at anode potential, which complicates the driving circuitry and makes it difficult to achieve uniform brightness across all digits. The tube uses a standard Noval 9-pin socket with an additional central pin.

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.

The GN-1, manufactured by STC and sold under the name ‘Nodistron’, was among the earliest commercially available Nixie tubes. The oldest documentation I could locate dates back to December 1959 (referenced below). The tube’s design reflects its age, with the digits being formed from wire rather than stamped from sheet metal like in most later Nixies. The GN-1 emits a distinctly orange glow, indicative of a mercury-free design, which likely results in a shorter lifespan compared to later models. Unlike more modern Nixie tubes, the GN-1 includes two evaporative getters, clearly visible on the left and right sides of the glass envelope. Additionally, its numerals are not mounted on a metal pin insulated by spacers but are instead secured between two mica plates and connected to the tube’s pins via thick wires. Interestingly, according to the datasheet, the tube has two anodes for use with direct and alternating currrent respectively.