Sylvania 64490 - M400/U 400 watt Metal Halide Light Bulb

The bulb came quickly and what looked to be in perfect condition. Once installed into the fixture supplied by a digital 400W ballast, it attempted to fire then shut down, after 4 cycles it established the arc and ran as it should. The next day it took 10 minutes to get started bu again established the arc and seemed to operate fine. Day three after an hour the bulb never gained full start cycling over and over again. I wouldn't recommend this bulb for a standard 400W digital ballast. Contacted the seller by email and still have not gotten a response.

Took a minute or so to initially spark an arc the first time I test fired, but after it finally lit I left it on to temper for about 15 minutes and has been working great since.
Kept my plants nice and stocky short with very little spacing between nodes. Fits "Cool-tube" type reflectors. Glad I didn't splurge on a way more expensive "brand name" horticultural bulb, got the results I was seeking with this one.

Works as designed, at a better price than they used to cost. Came quickly. No problems.