Switch from the yellow light of high-pressure sodium to the white light of metal halide without changing ballasts. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Color rendering index (CRI) is a measurement on a scale of 0-100 of how accurately the light from a bulb represents an object's true colors; the higher the number, the more natural the colors appear. Any CRI value over 80 will show colors true to life. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

Bulbs with an EX39 base number will not burst when they fail.

A traditional bulb type often found in older high-intensity discharge (HID) fixtures, these bulbs emit light with a blue/green tint. Use them to illuminate large outdoor areas, such as parking lots. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Color rendering index (CRI) is a measurement on a scale of 0-100 of how accurately the light from a bulb represents an object's true colors; the higher the number, the more natural the colors appear. Any CRI value over 80 will show colors true to life. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

Use these bulbs in standard sockets, panels, and appliances. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Bulbs with a warm light appearance have yellow tones. Bulbs with a neutral light appearance are commonly used in workspaces. Bulbs with a cool light appearance have white/blue tones and are good for inspecting. A bulb’s estimated yearly energy cost is based on 3 hours of usage per day at $0.11 per kWh.

Incandescent bulbs are traditional light bulbs. Many have been phased out due to governmental energy requirements, but some are still available for special applications.