LED tube lights are designed to physically fit in fixtures intended for fluorescent tubes. Some LED tube lamps are intended to be a drop-in replacement into existing fixtures if appropriate ballast is used. Others require rewiring of the fixtures to remove the ballast.
These bulbs work by passing a current through a tube filled with argon gas and mercury. This produces ultraviolet radiation that bombards the phosphorous coating causing it to emit light . Bulb life is very long - 10,000 to 20,000 hours. These type of bulbs are also very efficient, producing very little heat.