This 7/16" impact adapter socket is used to remove / install 1 in (26mm) and 1-1/8 in (29mm) square nuts.
The surface is blackened to form a dense oxide film on the metal surface, which can well isolate the metal matrix from the outside air, so as to avoid metal rust due to oxidation, it can significantly extend the service life of metal products, so that it is not easy to damage due to rust during use.