Bosch LSU 4.9 5-wire, wide-band O2 sensor. 

Compatible with the LM-2, LC-2, and MTX-L, SCG-1, DLG-1, PSB-1, and PSN-1. 

NOTE: The latest generation widebands are compatible with both the Bosch LSU 4.2 and 4.9. Please note that the sensor connector is different for each sensor. Reference the Sensor/ Sensor cable identifier image below. 

Another way to verify which sensor is being used is to connect the unit to the LM Programmer software. Please reference your user manual for more details.