Chrome vanadium steel with blackened-phosphate finish. For removal, inspection or replacement of heated and non-heated oxygen sensors. Windows and slots allow sockets to be fitted over wiring harness. Suitable for Titania and Zirconia oxygen sensors. Includes 3/8" 22 x 30mm offset oxygen sensor socket; 3/8" 27 x 74mm oil sender unit socket; 3/8" 22 x 80mm narrow slot vacuum sensor socket; 3/8" 22 x 90mm wide slot oxygen sensor socket; 1/2" 22 x 50mm offset heated oxygen sensor socket; 1/2" 27 x 85mm injector socket, and 1/2" 29 x 90mm oxygen sensor socket, in a tough storage case.