These adapters fit on BMW M50 M52 S50 S52 cylinder heads. Allows the use of an aftermarket sensor for more accurate water temperature reading in the cylinder head. Easily adapt M12x1.5 threads to accept a standardized 1/8" NPT thread commonly used for all gauges such as Oil temp, water temp, oil pressure, and more. Stainless Steel Male Thread Pitch : M12x1.5 mm Female Thread Pitch: 1/8" NPT Includes copper crush washer.