The Z568M is 4 inches high 100 mmand has a digit height of 2 inches50mm. It is therefore truly a giant amongst nixie tubes, presumably intended for railway clock applications and so on.
It is painted red, this was originally done to improve the contrast. There is also a non-coated version available, the Z5680M, but I could not obtain any of these at that time. Since I find the internal construction of nixies very beautiful, I removed the paint using a craft knife. This was a long and tedious process during which I was constantly afraid of breaking the tubes, particularly when excavating the seal at the top of the tube. Nevertheless the end results were worth it.
The glass cabinet was made from plates of glass cut to my specification at a local glass shop. The front panel is bevelled. I glued them together using a silicone glass glue/sealant, of a type intended for the construction of fish tanks. This is an incredibly messy and difficult process. The silicone sealant is an unpleasant substance to work with, and hard to remove from the glass when dry.
If you have java enabled on your browser, you will have seen a working simulation of this nixie clock at the top of this page. This uses an excellent java applet called DJClock by Naeem Malik, of Xanasoft. Note: A mouse click on the clock suspends the time, another mouse click will restart it. The digits template for this clock is shown below. This picture was obtained by laboriously photographing the clock from the same position, with different displayed times until I had all the digits 0 to 9. Cut and pasting in an image editor resulted in the template
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