Mercedes-Benz 250SL Dome Light Bulb Size

The Mercedes-Benz 250SL dome light uses a 6411 bulb size for interior illumination. The replacement chart covers 1966 to 1968 production years with corresponding bulb specifications.

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
1966-1968	6411

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 36mm length, SV8.5 base. 12V, 5W.	6411

Other Locations

Additional Notes

The Mercedes-Benz 250SL uses the 6411 bulb for its dome light across the 1966-1968 model years.
The 6411 is an ANSI-standardized bulb, meaning its physical and electrical specifications are governed by a recognized North American standard shared across the US and Canada.
The 6411 is a festoon-type bulb, a cylindrical form factor that seats by pressing its end caps into spring-loaded clips rather than twisting or plugging into a socket.
The 6411 measures 36mm in length, which is a critical fitment factor, as festoon bulbs must match the exact span of the fixture's retaining clips.
The 6411 uses an SV8.5 base, a designation that refers to the diameter of the metal end caps on a festoon bulb, in this case 8.5mm.
The 6411 operates at 12 volts and 5 watts, consistent with standard automotive low-voltage electrical systems.
Because festoon bulbs are sized by both length and base width, substituting a 6411 with a festoon bulb of a different length or base size would result in an improper fit in the 250SL dome light housing.