High Quality- Hardened and heat treated carbon steel. Built and constructed for spark plug removal and installation. The inner magnet won't wear out over time like traditional rubber seals and provides long life.Product Details- This 3/8" thin wall magnetic spark plug socket features a 12-point design, 16mm magnetic head and 14mm spark plug wrench. More Flexibility: The basic spark plug kit has a 360 swivel function degrees for maximum flexibility and allows access to the tightest areas.Unique Design - Slim magnetic design ensures it stays in place during installation and removal, so you don't have to no need to worry about losing it.Widely Used- Magnetic spark plug socket compatible with,mini like N54, N55, N63, Benz E90, etc. Note: The data are all manual measurement, please allow 1-3cm error, due to the light and display difference, there will be some color difference depending on the physical object received.