We're a company that likes solving problems. As some of you FA20 WRX enthusiasts have found, the OEM plastic breather/coolant fitting can start to leak over time, or worse, break when you're trying to remove/replace lines during a build or an AOS install.
So, in typical Killer B fashion, we have designed a no fail, no leak part. We've put our own performance spin on it as well, opening up the breather port, as the factory plastic piece is too restrictive.