Symbol Tubes Symbol tubes CD14 Rodan-Okaya CD14 top-view symbol tube GR-524 The GR-524 is an extremely rare symbol tube made by Rodan-Okaya. It shows the abbreviated days of the week in Kanji. GR-574 The GR-574 is an extremely rare nixie tube made by Rodan-Okaya of Japan. GR-707 The Rodan-Okaya GR-707. A small top-view nixie tube showing electrical symbols. Clearly intended for use in a multi-meter. This has the unusual feature of a side-nipple. The pin arrangement is also very unusual. GR-836 The Rodan-Okaya GR-836 is a large and extremely rare top-view 'nixie' tube. It has two Japanese symbols, which as far as I can tell mean 'power' and 'on'.