Nixies 5870/ZM1332 (and alike) and B-5750 share the same pinout, the same digit dimensions and shape, but not the height. Here is a side-by-side comparison of the two tubes during a test in my clock-to-be.
Left are ZM1332/5870's and the rightmost is a 5750:
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| Left to right: ZM1332, ZM1332, ZM1332, B-5750. |
