Double Tube
Double tube 4-pin CFLs feature two parallel tubes with a G24q 4-pin base for use with electronic ballasts. The 4-pin design enables dimming capability when paired with a compatible dimmable ballast — a key advantage over the 2-pin magnetic version.
Brand Naming Conventions
The 4-pin double tube is identified by each manufacturer with a suffix added to their standard double-tube product name:
- Philips (Signify): PL-C/4P — the base PL-C name plus "/4P" for 4-pin
- GE: Biax D/E — the "/E" indicates electronic ballast compatibility
- Sylvania (Ledvance): Dulux D/E — same "/E" convention as GE
If you are replacing a lamp and see "PL-C" without the ""/4P"" suffix, that is the 2-pin magnetic version — not this lamp. Similarly, "Biax D" without "/E" is the 2-pin version. Always check the suffix.
G24q Base Variants
Like the 2-pin G24d, the 4-pin G24q base is keyed by wattage to prevent mismatched installations:
- G24q-1: 10W and 13W lamps
- G24q-2: 18W lamps
- G24q-3: 26W lamps
These lamps are widely used in commercial downlights, recessed fixtures, and hospitality lighting where dimming and electronic ballast efficiency are required.