These are the ultimate in design from Manley Perfromance featuring a fully sculpted "Pro Flo" underhead design for maximum air movement in and out of the cylinder! All manley stainless steel valves feature double chrome stems and hardend tips for performance value over the long haul. All manley Subaru WRX and STi valves feature stock radius triple keeper grooves for superior valve retention! Manley stainless steel exhaust valves are fully forged and then machined from an Inconel (Yes the same thing high end turbocharger turbine wheels are machined from!) steel material giving them superior hardness and strength against heat. Manley pays extra attention to the swirl polishing, fully machined combustion faces of the head of the valve, and undercutting the stem to head diameter for a superior balance between strength and maximum flow! Fitments - Subaru 2002+ WRX EJ20 Subaru 2004+ WRX STi EJ2507