These senders screw into oil pressure extension to give accurate reading to oil pressure gauge on cars equipped with oil pressure gauge. High-quality, after-market unit. Made in USA. NOTE: 1967-1968 Cars originally had the same Sender but with a Spade connector not a threaded stud connector like the 65-66 and 1969-1970 cars. modification is required to 1967-1968 wire harness. We are working on adapter to simply this but it will not be available until late 2009.