Universal fit. May require additional adjustment or modification. Hardened chrome vanadium steel with built in rubber insert to hold spark plug steady.Thin wall bi-hex sockets designed to access narrow spark plug holes.Use with 3/8" drive ratchet or wrenchChoose the one that fits your spark plug size: 14mm, 16mm, 18mm, or 21mm. Choose Size 14MM $14.95 16MM $14.95 18MM $16.95 21MM $17.95 Ships same business day $14.95