The B-7971 is a 15-segment nixie tube manufactured by Burroughs. The first 14 segments can display all alphanumeric characters, and even custom symbol like arrows can be used. The 15th segment is an underscore. These tubes are perfect for all projects that require alphanumeric symbols or text. There tubes are rare and very expensive, they show up on ebay from time to time, and usually reach a price above 100$ per tube.