The Suzuki Gladius SFV650's turn signal bulbs are 1156 A Offset Pin size. Since it took me a while to figure it out, hopefully this will save someone else a bunch of searching.
I have no idea what the 1156 is for, except that one of the 1s indicates that it's a single filament bulb. The "A" is for "Amber" because the bike's turn signal cover is clear, so the bulb has to be amber tinted. And the "Offset" pin configuration means that the two bayonet pins are not exactly across from each other on the circumference .. one is "offset" from a straight-across position. So, the pins are closer to each other on one side, and farther on the other. Wacky.