With my build this was a must have!! I have a Drow sports cam cover heatsink and a stock airbox with aftermarket koso air filter. With the stage 3 DHM upgrade I was informed that a crankcase vent was in my best interest. The Drow sports breather vent would have hit the airbox. Now with this beautiful add on I can stack them both and still have a vent!! Another amazing product sold by DHM!!