A G4 light bulb is a bi-pin base lamp that runs off a low-voltage power supply. "G4" is a base designation which means the base has two pins and the gap width between the pins (center to center) is 4 millimeters.
Lamps (Light Bulbs and Tubes) - Open Lighting Product Directory (OLPD)
1.2W G4 LED Lamp - Kosnic
Pack of 10) LED G4 Light Bulb (Lamp) 2W 200LM 3000K
G4 LED 2W = 20W Capsule Light Bulb True Size Replacement For G4 Bulbs 12V
JAUHOFOGEI G4 LED Bulb 12V ac/dc Bi-pin Base Landscape Light Bulbs - 10W Replacement Halogen JC Bulb - 1 Watt 12 Volt Mini T3 Bulb for Under Cabinet Puck Lights
G4 FX Luminaire
1.5W LED G4 Bi-Pin 3000K Bulb (10w Halogen Replacement)
G4 LED Bulb Bi-Pin Base Light Bulb Lamps, 2W AC/DC 12V Daylight White 6000K, Equivalent to 20W Halogen Led, Non-dimmable T3 Bi-Pin Base Energy Saving LED Bulb for Home Landscape.10 Count (Pack of 1)
G4 LED Light Bulbs - Open Lighting Product Directory (OLPD)
DUMILOO G4 LED Bulb JC Type Bi-Pin Base Light Bulbs 1.5W AC/DC 12V Warm White 3000K 10W T3 Halogen Bulb Replacement for Under Cabinet Puck Light, Chandelier, RV, Landscape Lighting (12 Pack)
Philips TrueForce Core LED E40 HPL/SON Frosted 36W 5500lm 300D - 830 Warm White, Replaces 125W
G4 Bulb 1,5W, Portable, Dimmable – Audo Copenhagen
Light Efficient Design LED-8087M345D-G4 30 Watt LED HID Retrofit Lamp - EX39 Base - 3K / 4K / 5K - 4,200 Lumens - 120-277V