The seat occupancy mat is a sensor mounted in the front passenger seat. The emulator simulates a situation of a person sitting in the passenger seat with a seat belt fastened. To make the emulator work you need a diagnostic tool (like for , for , for etc.) to remove old errors of a broken seat mat that are stored in the control unit. Once you connect the emulator your diagnostic tool be to remove old errors and turn off the SRS/ warning. Unfortunately, the errors related to the safety systems are not removing automatically. Before purchase, please scan your car with a diagnostic tool to make sure your SRS/ warning is caused by a defective seat mat. Name:Car Seat Occupancy Mat Sensor SRS Bypass Emulator Fitment Type:Direct Replacement Install Fitment Type: Direct Replacement Install Condition: 100% New Fitment: For - A-Class W176 (2012-2018) For - B-Class W246 (2011-2018) Colour:As Shown Material:plastic Package Contents: 1 x Car Car Seat Occupancy Bypass MAT SRS Emulator Sensor Only