Buyer's GuideThe inner diameter of this magnetic swivel spark plug socket is 14mm (9/16inch),the inner diameter of the driver is 9.4mm (3/8inch),and the overall size is 305x17.8mm (12x0.7inch). Before purchasing,please ensure that the diameter of the hexagonal parallel side of your spark plug is also 14mm,otherwise this product will not be usable. Professional Spark Plug ToolMagnetic spark plug socket is essential tools for removing and installing spark plugs. Unlike ordinary tools on the market,our 14mm spark plug socket adopts a strong magnetic core+360 rotatable+12 point design,which can effectively protect the spark plug. Makes it easy and efficient for you to complete your assembly work. Exquisite CraftsmanshipEach of our thin wall spark plug socket is made of premium chrome vanadium steel material with exquisite craftsmanship. We are committed to creating high hardness,heavy structure and wear-resistant quality for you. The extended spark plug removal tool provides you with the additional extension range required for narrow positions. Easy to UseThe use of spark plug socket wrench is very simple. [1] Place the spark plug into the sleeve,and then gently place the sleeve into the cylinder,taking care not to fall to the ground. [2] Ensure that the spark plug is fully engaged in the sleeve. Rotate clockwise is tightening and counterclockwise is loosening (do not use excessive force during rotation).