Suzuki Motorcycle GSX-S750 front and rear turn signal bulbs both use a P21W size. The replacement chart covers 2015 to 2019 production years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the bulb type specified for both the front and rear turn signals of the Suzuki Motorcycle GSX-S750 across all listed model years.
The P21W operates at 12 volts with a 21-watt output, which is the standard wattage for single-filament automotive signalling applications.
This bulb uses a BA15s bayonet base, a single-contact fitting where the "s" denotes a single pin, distinguishing it from the dual-contact BA15d variant.
The P21W conforms to ECE (Economic Commission for Europe) standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
Because the P21W is single-filament, it serves only one lighting function per bulb, which is consistent with its dedicated turn signal role rather than a combined stop/tail application.
The front and rear turn signal positions share the same P21W specification across the 2015-2019 model years listed, meaning both positions draw from the same bulb type.
When replacing the P21W, the BA15s base must be matched precisely, as substituting a BA15d base bulb will not seat correctly in the socket.
Substituting a bulb with a wattage other than 21W in a turn signal circuit can cause the vehicle's flash rate to deviate from the intended timing, since most flasher relays are load-dependent.