The product is a lot of 4 genuine OEM AC Delco spark plugs specifically designed for the R45TS model. These spark plugs are manufactured by AC Delco, a trusted brand known for producing high-quality automotive parts. The spark plugs are interchangeable with the R45TS part number, making them a perfect fit for compatible vehicles. This set of spark plugs is essential for maintaining proper ignition performance and ensuring reliable engine function in your vehicle.