Hi Jonathan, this Anderson lower is made of 7075-T6 aluminum. It is not RF-85 treated.

7075-T6 Aluminum
full specs
You could pay more, or put it together yourself, but why? These Anderson AR-15 complete lower receiver assemblies are the perfect foundation for any new modern sporting rifle build. Based on a 7075-T6 aluminum lower receiver, this unit is fully assembled with a quality lower parts kit. It has an A2 pistol grip and a collapsible stock installed. Just pin on your upper assembly of choice and you are off to the range or field. These aren't going to last, grab yours today!
Specifications and Features
Anderson Anderson-Complete-Lower
7075-T6 lower receiver
Installed lower parts kit
A2 pistol grip
6 position collapsible stock
Black