Neon Coated Tubes are made using electrified, luminous tube lights that contain rarefied neon or other gases. They are the most common use for neon lighting. The neon sign is an evolution of the earlier Geissler tube, which is an electrified glass tube containing a rarefied gas (the gas pressure in the tube is well below atmospheric pressure). When a voltage is applied to electrodes inserted through the glass, an electrical glow discharge results.