This lot of four Motorcraft spark plugs, model AGSP33C, is brand new and has never been used. They are compatible with Ford Probe I4 and V6 engines, and are made of high-quality copper material with a standard configuration. These spark plugs have a thread diameter of 14mm and a hex size of 5/8in, and operate at a voltage of 12V. The AGSP33C model has interchange part numbers of STK45, 5613796, and SP445, as well as an OE/OEM part number of AGSP33C. They are not a vintage part and are not considered a performance part. This lot of spark plugs is perfect for those needing to replace their old or worn-out spark plugs. They are easy to install and come from a reputable brand, Motorcraft. With these spark plugs, your vehicle will have improved ignition performance and run more smoothly.