Referring to either a lamp, or a luminaire using a lamp, that is Tubular, 3/8" in diameter, double-ended, and fits in a pair of RSC sockets. Lamp wattage can be from 100W to 500W (ANSI FCL) to 1000W (FFT) to 1500W (FDB). Most broad and asymmetric-reflector-cyc fixtures use the T-3 lamp.
Example of a T-3 striplight, usually used as a cyc ground row:
View attachment 4783
Altman Ground Cyc
Example of a T-3 striplight, usually used as a cyc ground row:
View attachment 4783
Altman Ground Cyc