The ATK GT250R uses the 5008 bulb in both its front and rear turn signal positions across the 2011-2014 model years.
The 5008 is an ANSI-standardized bulb type recognized in the United States and Canada, operating at 12 volts.
It is a single-filament bulb, meaning it serves one lighting function rather than combining two functions such as braking and signaling within a single unit.
The 5008 uses a BA15s bayonet base, which is a single-contact bayonet mount with a 15mm collar width, a common base type in automotive and motorcycle applications.
The 5008 is a lower wattage variant of the 1156 bulb, sharing the same BA15s base but drawing less power, which makes the two types physically similar yet not electrically identical.
Because the 5008 and 1156 share the same BA15s base, the 1156 can physically seat in a 5008 socket, but the wattage difference means substituting one for the other may affect turn signal flash rates or circuit load.
The uniform use of the 5008 across both front and rear positions on the GT250R means a single bulb type covers all four turn signal sockets on the vehicle.