This is GNP's T-6061 solid aluminum, hard anodized Timing Belt Guide. This Timing Belt Guide has been designed to be wider and stronger than the stock Subaru piece, while keeping the proper tolerance to ensure smooth timing belt operations at all times.

What this does is help eliminate what's called belt whip. Which could lead to very bad things for your motor. Belt whip is caused by changes in torque that your motor goes through, usually by being hard on and off the throttle. We have engineered this piece with an extended length and width to apply more coverage for the timing belt and hard anodized it to provide a smooth belt track.
This part is a direct replacement for the stock flimsy piece, and can be added to just about any DOHC Subaru 2002 and newer.
Because you want to protect your investment while enjoying it to it's fullest.