Double Star's Picatinny Rail Adjustable Gas block is in house from 6065 T6 aluminum and finished with a black hard coat anodize. The stainless steel adjustment screw is held in place with a brass tipped stainless steel set screw. The brass tip prevents damage to the threads on the adjustment screw.
AR-15, Issue:11, Page:015
Big Book Catalog, Issue:73, Page:022
SPECS: Material: 6065 T6 Aluminum. Inside Diameter: .750.