The Turbo XS Type H Hybrid Blow off valve is ideal for Mass Air Flow (MAF) metered cars that want some noise but don't want the problems associated with venting to atmosphere. The Hybrid Type H is CNC machined out of billet aluminum and is specifically designed with high boost applications in mind. This BOV recirculates 50% of air and vents to atmosphere 50%. This valve requires a vehicle specific mounting flange, sold separately. This 50/50 BOV will not work on a WRX/ STi TMIC (Please see the WS-HYB or WS08-HYB)