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. Bulbs with a warm light appearance have yellow tones. Bulbs with a neutral light appearance are often used in workspaces. Bulbs with a cool light appearance have white/blue tones and are good for inspecting. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

LED bulbs last longer and are more efficient than fluorescent bulbs. They generate little heat and withstand vibration. Socket-ready bulbs work with most instant-start electronic ballasts, but not all. For a full list of compatible ballasts select a part number and view product detail. Ballast bypass bulbs eliminate the need for a ballast so the socket must be wired directly to the power source.

Fluorescent bulbs are energy efficient, but they contain small amounts of mercury (for disposal information, visit www.epa.gov/cfl). Plastic-coated glass bulbs are shatter resistant; the coating retains glass shards if they break.