LED High Bay DirectFit Lamps are the plug-and-play, energy-saving replacements for HID bulbs in existing high bay fixtures. The lamp screws directly into Mogul-based sockets and operates off the existing ballast - no rewiring or extra labor required. With current sensing technology, the lamp adjusts the lumen output to match the existing ballast. In other words, one lamp suits many installations!Choose from two models based on your retrofit needs: the enclosed-rated 145W replaces 175W to 400W HID, while the 250W version is equivalent to 750W - 1000W MH (not for enclosed use).