Includes (4) BU8H Spark Plugs. Thread Size: 14mm, Thread Pitch: 1.25mm, Seat Type: Gasket, Reach: 12.7mm (1/2"). Hex Size: 13/16" (21mm), Terminal Type: Solid, Overall Height: ISO, Gap:.016" (0.4mm). Material: Nickel, Type: Standard, Size: 2.5mm, Projection: Non-Projected. NGK standard plugs are constructed for longer life and optimum performance. Compatible with the Following: Autolite: 2852,Champion: 885M, L6VC, QL16V, QL6VC, NGK: stk 6431