Need help with this Part

hey guys new on this site well i need help i have a 1993 400e and there is a small element type sensor which goes and attaches to the front ait pipe(hose) on the driver side (other side doesnt has it the part number reads0095426817,
first what is this part and what s its function mine just came off and i wanna know coz it didnt make any difference in teh car,,,,,
and where can get it cheaper
thanks
400e