**Final Sale Item** By using this light weight alternator pulley, your Subaru BRZ or Scion FR-S will see gains in horsepower & torque through reduction in rotational weight & a much higher efficiency. This is due to the parasitic effects that the factory pulley has on the vehicle's boxer engine. An unlike an underdrive pulley, you will NOT see dips in alternator voltage, power assist, and air conditioning effectiveness.Made of lightweight aircraft duralumin A7075. About 110g lighter than stock. Gold anodized finish.