The GR-B is an early nixie tube manufactured by Rodan-Okaya of Japan. It is unusual because it includes a display of the number 10. The tube looks to be a variation of the GR-1, judging by the style of the labelling on the tube. This would mean that the tube does not contain mercury, so it would have a short lifetime. There is also a version of this called the GR-542 that, judging by the label style, appears to be a version of the GR-201, which would mean that that tube did contain mercury.
| Digit size | 19mm |
| Min current | 1.5mA |
| Max current | 3.5mA |