Genuine Bosch air temp sensor.
Thread: M12x1.5mm
​Range: -40deg to 140deg
Accuracy at 25°C: ± 1.4°C
Accuracy at 100°C: ± 3.4°C
Nominal resistance: 2.5 kOhm ± 5 % (at 20°C)
 
A must have for any m57n2 conversion,  replaces the old bmw twist style sensor that is prone to failure 

The main benefit of the sensor is the combination of a high quality production part and a robust and compact design over the oem bmw style.