What is the main differences between metal halide lamp i see at marine dealers that are like 500 dollars and say a fixture from www.1000bulbs.com For example
250 Watts, BT-28 Sylvania Brand Metal Halide, E39 Mogul Base, Length 8.31", Diameter 3.50", Kelvin 4200, CRI 65, ANSI M58/E, Universal...