This listing is for (4) sensors factory sealed. The Genuine GM Park Assist Alarm Sensor 84153946 is a direct replacement sensor designed specifically for GM vehicles. This OEM sensor is authentic and guaranteed to provide accurate parking assistance. It replaces part numbers 84078131 and 39088465, ensuring a perfect fit for your vehicle. With a focus on quality and compatibility, this sensor is a reliable choice for enhancing your parking experience. These are an electrical item and are returnable if unopened. Shipping is free on this item. Thank you