The Porsche 968 uses the P21/5W bulb for both front and rear side markers across all listed model years, 1992-1995.
The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single glass envelope, rated at 21 watts and 5 watts respectively on a 12-volt circuit.
The P21/5W follows the ECE (Economic Commission for Europe) standard, a regulatory framework adopted across Europe and numerous other markets worldwide.
This bulb uses a BAY15d bayonet base, which features two offset pins at different heights to ensure correct polarity orientation during installation, preventing the filaments from being connected in reverse.
The front and rear side marker positions on the Porsche 968 share the same bulb specification, meaning a single bulb type serves all four side marker positions on the vehicle.
The BAY15d base is distinct from the single-filament BA15s base; the two types are not interchangeable, as the dual-pin offset configuration of the BAY15d is specific to dual-filament applications.