I BUY THIS ON AMAZON AND IT WAS NOT WORKING EXCEPT FOR A SENSOR AND I SENT IT BACK AND A REPLACEMENT WILL NOT WORK DO YOU HAVE A RECEIPT FROM UPS WHEN IT WAS DELIVERED . I CANNOT CONTACT AMAZON TO SOLVE BUT NO LUCK. I BOUGHT THIS FOR MY OFF-ROAD AND IT HAS 4 SENSORS AND PERFORMS VERY GOOD WITH NOISE. I'M STILL TRYING TO CONTACT AMAZON BUT I CANNOT ACHIEVE SUCCESS ON AMAZON.