It's an old reliable with a history of good service, the FB40T12 u-shaped fluorescent light bulbs.  These are sometimes called U6 bulbs by the distance between the legs of the lamp, which is 6 inches.  With the advent of smaller light fixtures such as 2x2 fixtures, manufacturers developed a lamp which could fit into that space and also have a great light output.  Like most fluorescents, FB40T12 super saver fluorescent light bulbs are a great way to save energy over standard u-shaped light bulbs.  Compared to it's less efficient counterpart, the FB40T12, the FB40T12 super saver u-shaped is definitely an improvement which will save you money in the long run.  They operate on 34 watts instead of the standard 40 watt version.  There are many people changing these out to a FBO32T8 which is even more energy efficient.  Of course, the ballast would need to be changed to an electronic ballast, as the magnetic ballast for the lamp will not operate T8's, but the socket configuration is identical. You can tell the difference between a T12 and a T8 by measuring the diameter of the bulb. The FB40T12 bulb will be 1 1/2 inch in diameter, compared to 1 inch for the FBO32T8 light bulb.  The spacing between each end of the u-shaped tube is 6 inches regardless of whether it's T12 or T8.  The old technology T12 is the standard cool white or warm white lamp that's been used in offices throughout the world and the logical energy saving replacement would be the 3500K or 4100K FBO32T8 lamp.  As with all fluorescent bulbs, they rely on ballasts inside of the fixtures in order to make them work. Almost all fixtures for these bulbs come with ballasts already mounted and wired. The ballast is important because it is specific for each type of lamp.  You can't change from one type of fluorescent to another without changing the ballast in most cases.  On some occasions there may be a ballast that is made for several different types such as in the case of T8 lamps. Most of the time the ballast and the lamp are matched electrically and so it's good to make sure the ballast you have is the right one for the lamp you choose.

You can get these in almost any color you want including the more desirable full spectrum light.  The full spectrum has special phosphors that give it a similar color to daylight or natural sunshine.  These are also available in FB40T12 u-shaped fluorescent light bulbs.  It produces light the way our eyes naturally use it, giving better visual acuity and reducing problems like eyestrain.  But fluorescents can come in many other colors as well and are identified by their Kelvin temperature. Some of the choices are 3500K, 4100K or 5000K and depending on your color scheme, one of these color choices will work best for your situation.  The 4100K or cool white is probably the most popular as it offers a clean, efficient light used in offices almost everywhere across the country and throughout the world.  However, if you want the whiter full spectrum color, then the 5000K color temperature would be the one you want.  Many suppliers don't have all the variations of color in this lamp, but we do.  We even have this lamp in a Vitalite which is probably the premier full spectrum tube in the industry.

We keep plenty of these in stock so you will always have a good source to buy from, ServiceLighting.com. Use us for any type of light bulbs you have, but keep us in mind the next time you're looking for something that isn't all that common. And because the FB40T12 u-shaped fluorescent light bulbs are made by Sylvania, you know that you're going to get the best service from Sylvania's premier online distributor, ServiceLighting.com.  Having the light bulbs you need like this one make us special among others, we have the entire Sylvania catalog available to you.  That means you get the best quality light bulbs and service to your home or business.

Because it's still very pervasive in many office environments across the country, we make the FB40T12 fluorescent light bulbs a substantial part of our offering. There will probably never be a time when these will not be in use. Remember that there are many types of fluorescent lighting, we describe some of the most common used in commercial lighting here.  Whatever type of fluorescent you choose or have, you will be saving energy while getting the most light you can for your money.  We have a large inventory of fluorescent bulbs for nearly every type of light fixture in the field.  If you need help identifying a light bulb, our customer service representatives can help you determine what you have.