Chouinard “ALCOA” Carabiners
Made from the late 1950 until 1968s, this version of the Chouinard “ALCOA” carabiner had “820 ALCOA 7075” on one side of the spine and “Chouinard” on the other. The first versions did not have the Chouinard name on the carabiner it was added after the initial run.
These were well designed carabiners. The fact that all of them in our collection still open and close like they are supposed to and show only cosmetic wear says a lot about their simple and sturdy construction.
ALCOA stands for Aluminum Company of America
7075 denotes the alloy type used to construct the carabiner.
820 has been a bit of a mystery but is probably either a design designation or a batch number
Additional information can be found on this Supertopo thread. Ray “Fritz” Brooks has diligently compiled a complete timeline of Chouinard/Black Diamond carabiner history.