I'm sure you do understand, but just to be absolutely clear, what Jimble means isn't anything to do with the actual orientation of the bulb, but rather the polarity of the 2 metal connectors where it plugs in. Unlike halogen bulbs when it doesn't matter which one is positive or negative, LED's do mind, so if when first plugging in a LED bulb it doesn't work, rotate the bulb through 180° in the connector and it **should** work.