OEM Oxygen Sensor Mitsubishi Info

Hey I just bought a New OEM Mitsubishi Oxygen Sensor (O2) from ebay and am not sure if its for before the cat and after the cat. The part #MD198529 dated 4/19/04 and its plug and play design. Only paid $21.49 ! pretty good considering Bosch aftermarket are around 50-60$ -- any info on this part or maybe a link to show me the info will help greatly :smt045

Find the plug for your front o2 sensor in your motor bay.

Unplug the o2 sensor and test fit it to the one you bought.

If it fits then its a front o2 sensor..if it doesn't its a rear o2 sensor.

The front and rear o2 sensor plugs are different.