Enduro Engineering 33-071 Ultra Rear Disc Guard

The Enduro Engineering Ultra Rear Disc Guard is an excellent insurance policy for your brake disc on rocky trails and harsh terrain.
With its construction of lightweight and incredibly strong aluminum alloy, the guard shrugs off serious hits and deflects potential damage away from your brake disc.
Preventing damage to your rotor will save you money, but more importantly your rear brake will remain operational and you'll keep your rear wheel from locking up with a bent rotor.
If your Enduro Engineering Ultra Rear Disc Guard does take a big hit, don't worry, snag a replacement fin (part number 1393340001) and you'll be good to go.
There's no need to buy a whole guard because while the replaceable fin takes the damage, the main bracket/carrier is designed to stay out of harm's way.