The PERRIN crank pulley is machined from 6061T6 billet aluminum, anodized black or red and laser etched for increased belt life and a precision fit. Precision machined grooves, tightly sync with all OEM and aftermarket belts. While the PERRIN Performance crank pulley fits great on all 1993 or newer Subaru boxer engines, the rear belt keeper is now minimized to make installation on 2008+ Subarus easier! The PERRIN Performance Crank Pulley weighs just 1.2 lbs, which is 4-pounds lighter than the stock OEM crank pulley. This reduction in weight from the crank shaft is equal to removing more than 100 lbs of vehicle weight! Throttle response, horsepower and torque are all increased with this easy to install part.