The seat occupancy mat is a sensor mounted in the front passenger seat. The emulator simulates a situation where a person is sitting in the passenger seat with a seat belt fastened. To make the emulator work, you need a diagnostic tool to remove old errors from a faulty seat mat stored in the control unit. Once connected, use your diagnostic tool to clear the errors and turn off the SRS warning light. Errors related to safety systems cannot be removed automatically. Before purchase, scan your vehicle with a diagnostic tool to confirm the SRS warning is caused by a defective seat mat. Name: Car Seat Occupancy Mat Sensor SRS Bypass Emulator Fitment Type: Direct Replacement Fitment: For A-Class W176 (2012-2018), For B-Class W246 (2011-2018) Color: As Shown Material: Plastic Package Contents: 1 x Car Seat Bypass Emulator Sensor Note: Light reflection and different display settings may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3 cm.