Straight pins base guide

GX24q bulb base

Four-pin keyed CFL base family

GX24q is a four-pin keyed plug-in family. The suffix, such as GX24q-1 or GX24q-3, is part of the compatibility check.

Reviewed August 28, 2026
24 mm keyed familyNominal measurement · drawing not to scale
Connection
Straight pins
Electrical context
Requires the matching ballast, suffix, and lamp wattage
Also called
Four-pin GX24, PL-T base

How to identify GX24q

  1. Read the complete GX24q suffix.
  2. Compare key position and pin layout.
  3. Read ballast and wattage markings.

Where it is commonly used

Commercial downlightsPlug-in CFL fixturesHospitality lightingInstitutional fixtures

Common use is a clue, not proof. The fixture label and model documentation take priority over a visual match.

Bulb shapes sold with this base

You may see these shapes with a GX24q base. The base code does not guarantee the bulb width, length, beam angle, or clearance.

Triple tubeQuad tubePlug-in LED

Before you buy a replacement

  • Do not omit the numeric suffix.
  • Similar-looking bases are deliberately keyed differently.
  • LED retrofits have product-specific wiring requirements.

Quick answers

Questions about the GX24q bulb base

What is a GX24q bulb base?

GX24q is a four-pin keyed plug-in family. The suffix, such as GX24q-1 or GX24q-3, is part of the compatibility check.

What size is a GX24q bulb base?

GX24q has a nominal 24 mm keyed family. Pin spacing is measured from the center of one pin to the center of the other. Use the printed base code when available because a visual estimate is not conclusive.

Where is a GX24q bulb base commonly used?

Common examples include commercial downlights, plug-in cfl fixtures, hospitality lighting, institutional fixtures. Fixture type is only a clue; confirm the code on the bulb, socket, fixture label, or manufacturer documentation.

Can I choose a GX24q replacement by appearance alone?

No. Match the GX24q connection first, then verify voltage, actual input wattage, bulb dimensions, fixture restrictions, controls, and any enclosure or location rating required by the installation.