This 3-piece sensor and switch socket set is ideal for removing oxygen sensors from the exhaust manifolds on many models. The switch sockets are constructed of vanadium and molybdenum steel for strength and durability with a black oxide finish to fight off rust. The oxygen sensor socket can fit on almost every car. The 3/8" Dr. 7/8" (22 mm) flare nut socket is for vacuum switch & oxygen sensor service on computer controlled engines. All tools come in a storage case for easy transportation. Delivery includes two 7/8" x 3/8" drive vacuum switch sockets and one 7/8" x 1/2" drive oxygen sensor socket.