A small u-shaped or H style (biaxial shape) tube which is the most common basic
compact fluorescent bulb shape.
The DAMAR designation for this style of tube is "TT" or Twin Tube.
The GE trademarked name for this style of tube is "Biax".
The Osram trademarked name for this style of tube is "Dulux".
The Philips designation for this style of tube is "PL".
Single
Double
"Quad"
Triple
Quad
Long
DAMAR
TT
DTT & DDTT
DTT
CFM
N/A
LTT
Osram-Sylvania
DS
DD
N/A
DT
N/A
DL
Philips
PL
PL-C
PL-C (22mm)
PL-T
N/A
PL-L