The Tester's pin socket reads the continuity at each end of the lamp. If the indicator light glows and beeps, all is well. If it does not, then the cathodes or pins are faulty.
To check if your lamp has still has gas in it, simply touch the testers antenna to the tube and press the "Lamp Tester" button. A tube with gas will light dimly when touched by the Tester's aerial, but a tube without gas will remain dark. However, even if the tube lights up, there still may be a continuity problem, so be sure to use the Tester's pin socket as well.
The Kino Flo Lamp Tester's Antenna-aerial can also be used to check a lamp's color temperature or a visual effects color, such as when many tubes are mixed together in a case. The antenna-aerial feature can be used to test neon tubes as well.
The Lamp Tester is lightweight, durable and comes complete with a 9-volt battery. Kino-Flo Part# TST-LAMP