Incandescent lamp (General Lighting - T Series), is a specially shaped bulb for both general lighting and most typical application is used as indicator lamps for different machines and devices to indicate if they are working properly. It has a wide range of industrial or commercial lighting applications. T series filament bulb are generally known as tubular bulb, the most common model includes a series of small tubular bulb shape including T18 | T22 | T25 | T28 | T30 | T32. They are used in smaller fixture with smaller screw base. They are made in an extremely wide range of sizes, wattages, and voltages, which power ranges from 15W to 60W. T series incandescent light bulb can be seen in almost all E12 | E14 Edison based, while optional bayonet base such as B15d is also available.

The incandescent light bulb or lamp is a source of electric light that works by incandescence, which is the emission of light caused by heating the filament until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxidation. It usually contains a stem or glass mount attached to the bulb's base which allows the electrical contacts to run through the envelope without gas/air leaks. Small wires embedded in the stem support the filament and/or its lead wires. Current is supplied to the filament by terminals or wires embedded in the glass. A bulb socket provides mechanical support and electrical connections. They require no external regulating equipment like driver or ballast, and work equally well on either alternating current or direct current.