Will this fit my old fluorescent fixture?

It is a 48-inch T12 tube with a medium bi-pin G13 base, the common size for 4-foot shop and ceiling fixtures. Check that your fixture takes 40-watt T12 tubes and has a working ballast.

Does it need a special ballast?

It runs on the ballast your fixture already has, as long as that ballast supports 40-watt T12 tubes. It is not a plug-and-play LED tube and does not bypass the ballast.

What color is the light?

It is 4,100K cool white, a neutral white that sits between warm indoor light and daylight. It reads slightly cool, which suits garages, workshops and utility spaces.

How is it different from an LED tube?

An LED retrofit uses less power and lasts longer, but often needs ballast bypass or a compatible ballast. This tube is a direct replacement for standard fluorescent setups.

Yes, it is part of Philips' ALTO line, which is made with reduced mercury. It still contains mercury, so recycle it at a proper facility rather than putting it in household trash.