Manfacturer: Duro-Test Corp.
The unique AT-19 light bulb was an exclusive product manfactured by Duro-Test Corp and is one of their many unique, niche products. When I was a kid, I was intrigued by these bulbs and that many of them had heat deflectors which worked with the enlongated crown to improve optics or something, ha. Actually they were designed to allow 12% less heat at the top portion of the lamp, and also to permit easier screwing/unscrewing in recessed cans (you just screw the bulb with hands on the crown!). They were made in AT-19 and AT-21 envelopes, came in a variety of wattages and were only sold by Duro-Test and its divisions like Duro-Lite and Luxor. The most common finishes for these lamps are clear and inside frosted, although some "brite-white" ones were also made. Also made with the AT shape were some odd finishes like ATC reflector floods (with silver coating on neck of bulb), Crystalier, bug lights, and spun-glo Flamescent. Of these, I have both the clear and frosted versions shown here, and a Crystalier one shown elsewhere on the Incandescent Lamp page. Traffic signal lamps were also made in the AT shape and DT's ones were (still are) very popular with many cities and DOTs because of their lower premature failure rates than competitive ones, which also only came in the A shape. Some of you may know that Duro-Test went out of business in 2000, that fortunately turned out to be only temporary as DT was revived a year later...and the AT bulbs are still offered.
Lamp: Standard incandescent
Wattage: 40-100
Voltage: 120, 125, 130
Bulb: AT-19
Finish: Inside Frosted, Clear
Base: E-26s Brass Medium Base
Class: C
Filament: C-9 w/ 4 supports (sometimes w/ 7 supports)
Lamp Life: 2500-7000 hours
Manf. Date: -
Country of
Orgin: USA
