Limited! These are machined in-house here at PLM using our latest Haas 5-axis CNC machines. The Precision Works Coolant Breather Fitting Assembly is an essential upgrade for your 2015+ WRX FA20 DIT. The OEM housing is constructed from 100% plastic, making it highly susceptible to brittleness and breakage, especially when installing an Air Oil Separator (AOS). Our fitting assembly is expertly crafted from 6061-grade billet aluminum, offering exceptional strength and longevity.