Standard BA15s signal bulb — two per pack so both sides get replaced at once.
The BOSCH P21W is a single-filament 12 V automotive bulb used in front turn signals and, depending on the housing, in stop and reverse lights. Each pack holds two 21 W bulbs with a BA15s base.
BA15s base for direct replacement
The single-contact bayonet fitting drops into standard OE headlight and tail-light sockets with no adapters or wiring changes. Fitting is done by hand, on most cars through the access cover at the back of the lamp unit.
Two bulbs per pack for balanced replacement
The twin pack lets you renew the left and right side together, so both filaments glow with matching brightness. Keeping the spare in the boot is handy for a roadside check.
ECE-approved signalling light
Part of the BOSCH Pure Light range, the bulb meets the requirements for vehicle signalling lamps. Its 21 W rating at 12 V matches original equipment, keeping the flasher relay timing unchanged.