The Mercedes-Benz 280SL uses a P21W bulb size for both front and rear turn signal applications. The replacement chart covers 1968 to 1971 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz 280SL uses the P21W bulb type for both front and rear turn signals across the 1968-1971 model years.
The P21W is an ECE-standard single-filament bulb rated at 12 volts and 21 watts, designed specifically for signalling applications such as turn signals and brake lights.
P21W bulbs use a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar width.
The BA15s base designation indicates a single-contact configuration, distinguishing it from the dual-contact BA15d variant, which is not interchangeable with the 280SL's turn signal sockets.
The ECE designation on the P21W reflects compliance with United Nations Economic Commission for Europe regulations, a standard adopted across European and many worldwide markets.
The uniform use of P21W across all four turn signal positions on the 280SL means front and rear positions share the same bulb specification, requiring no positional differentiation when sourcing replacements.
At 21 watts, the P21W operates at a wattage level that is calibrated to meet ECE visibility requirements for turn signal brightness, and substituting a lower-wattage bulb may affect regulatory compliance.