This is a BMW ATC-300 Transfer Case Sprocket Assembly.
This sprocket is for BMW AWD models 328i, 335i, 528i, 535i, 325xi, 328Xi, 335xi, 528xi and 530xi.
It is a 41 Tooth Gear sprocket and can be used with for OEM numbers (27107599690, 27107599693, 27107613153)