Check local auto parts stores like AutoZone, Advance Auto Parts, or O'Reilly Auto Parts. They usually carry a variety of wiper blades, including replacements for your 2006 Subaru Outback.
Online Retailers:
You can also find wiper blades online on websites like Amazon, Walmart, or directly from the Subaru parts website. Search for specific wiper blades compatible with your vehicle's model, year, and make.
Subaru Dealership:
Alternatively, you can contact your local Subaru dealership to order a genuine replacement rear window wiper specifically designed for your 2006 Outback.