This aluminum coolant fitting is designed and manufactured to precise tolerances to fit the OEM application but with notable improvements in function. This Water Hose Fitting is made from high strength aerospace aluminum, Grade 6061 T6511. Also,it was designed to maximize the resistance to breakage. In addition to this, the coolant flow path through the center of the fitting is optimized to maximize coolant flow. There are no sharp corners on this fitting so that the coolant will not be disrupted as it passes through. This product is an OEM replacement for the plastic fitting on PN 11537541992 and 11537544638. This Water Hose Fitting for : N52 X3 N20 (2.0L turbo) Z4 2013 & up N54 (3.0L twin-turbo) motors 335i, 335xi, 135i. N53 (3.0L non-turbo) 2006 - 2010 325i, 330i, 525i, 525xi, 528i, 528xi, 530i, 530xi. This Water Hose fitting also fits the next generation N55 motors in all chassis. Material: Aluminum Size: 80 x 80 x 62mm/3.15 x 3.15 x 2.44" You will get: 1 x EPDM O-ring 1 x Billet aluminum fitting 1 x Stainless steel hose clamp