Hivac Hivac of the UK are known for the distinctive gold color of their anodes, which makes their tubes particularly collectible. GR10J The GR10J numicator by HIVAC. A lot of HIVAC tubes have a distinctive gold-colored anode. GR10M/U The GR10M/U is a medium-sized nixie tube made by Hivac of the the U.K. XN3 The XN3 numicator is a medium-sized nixie tube made by Hivac of England. XN12 The Hivac XN12 numicator XN-13 Hivac XN-13 Numicator. This has Hivac's signature gold-colored anode grid.