Symbol Tubes Symbol tubes CD14 Rodan-Okaya CD14 top-view symbol tube 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'.