Volkswagen Thing License Plate Bulb Size

The Volkswagen Thing license plate light requires a bulb size of 12821 for the lighting system. Data for the specific bulb size covers the range from 1973 to 1974.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1973-1974	12821

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12821

Other Locations

Additional Notes

The 1973-1974 Volkswagen Thing uses the 12821 bulb for the license plate position.
The 12821 is a Philips part number designating a miniature wedge bulb in the T10 form factor with a W2.1x9.5d base, rated at 12 volts and 5 watts.
The T10 wedge base is a push-in fitment that does not use a separate metal base or locking mechanism, relying instead on the tension of the socket walls to hold the bulb in place.
The W2.1x9.5d base designation describes a wedge-type contact where the number values define the pin spacing and insertion depth, which determines physical compatibility with a given socket.
At 5 watts on a 12-volt circuit, the 12821 draws approximately 0.42 amperes, which is typical for low-current license plate illumination applications.
The T10 designation refers to the bulb's tubular envelope, with the numeral indicating a width of 10 eighths of an inch, a sizing convention common in miniature automotive bulbs.
Because the 12821 is a manufacturer-specific part number from Philips, equivalent bulbs from other manufacturers are cross-referenced by their base type and electrical ratings rather than by this number alone.