This fixture is an LED replacement for conventional HID and fluorescent high bay systems. It is ideal for manufacturing, warehousing, commercial, retail, and other large indoor spaces. It is most effective with mounting heights ranging from 15 to 40 feet and ambient environments between -40 and 131F. These high bay fixtures are made with a die-formed aluminum alloy chassis. Powder coated heavy-duty code gauge steel makes the channel, and the channel is designed to resist twisting and bowing. It has integrated fins in the chassis for superior cooling through natural convection. Predicted life of 100,000 hours, with 92 percent lumen maintenance at 60,000 hours. With these fixtures you can choose between wide, medium and narrow light distributions. You can also choose between clear and diffuse lenses for extra glare control and LED protection, if needed. Finally, you get precision-formed optics which utilize reflective Alanod MIRO-5 specular-aluminum.