Manfacturer: GTE Sylvania
This GTE Sylvania 100 watt BT-25 lamp was manfactured from 1975 to 1980, and one can tell by the clear band on the end, this was a trait on all Sylvania phoshor coated mercury vapor lamps of this time. Prior to 1975, Sylvania lamps had cleartops, and after 1980 Sylvania finally went to fully phosphored ends. Also, in the early 1980s Sylvania stopped making BT-25 lamps in favor of the ED-23 1/2 envelope, although they kept the BT shape for BT-28 and large sizes. Then in the 1990s Sylvania went back to the BT shape in a new, rounded ET-23 1/2 envelope, and continues to this day. This lamp is NOS and still in its sleeve.
Lamp: Mercury Vapor
Wattage: 100 watt
Starting Voltage: 240 volts
Operating Voltage: 130 volts
Ballast Type: H-38
Color Temperature: 3700 degrees K
CRI: 45
Light Output: 4800 Lumens
Bulb: BT-25 Hard Glass
Finish: Deluxe White
Base: E-39s Brass Mogul Base
Class: -
Filament: -
Lamp Life: 24,000 hours
Manf. Date: May 1978
Country of
Orgin: USA
