I finally got my hands on some! This is an IN-4 nixie tube (a type of numerical display used in Russia from the 50s to the 80s) that I got online a couple months ago. They're like a small bulb or vacuum tube filled with neon gas. They have a grid, as the main anode and number shaped metal structures on the inside, acting as cathodes, and when electricity passas through the gas and strikes a cathode, it lights up the cathode that electrical power is hooked up to. Unfortunately, they are not manufactured anymore, making them hard to find. Also, many people have made clocks out of them, which look very nice in my opinion. I also have some IN-14 tubes on their way so, look forward to a picture or two of those.