Assitance required on Lambda sensor details

[kick98]

car c180
2002
w203
111 engine
1998cc
auto

I have had a diagnosis today of requiring the Lambda sensor i am led to believe there are two sensors..i require the one at the front of the exhaust ie nearest engine , i see on ebay that they are worded as the 4 wire pre cat or lambda sensor with plug etc , *****am i looking for a 4 wire pre cat ?





____________________________________
mercedes sprinter engines