Wow, original stainless steel C&I  Rolex Fixed link hollow rivet band.  Dated 79.   C&I was based in the United States and manufactured meaningful quantities for about two decades starting in 1959. These bands had thinner hollow rivets and a lighter gauge steel than its Swiss-made counterpart.   Hard to find these.  Has normal age patina as well. Never polished or brushed.  Comes with both ends and working clasp. Vintage Rolex.  Found in my parents jewelry drawer of all places while cleaning out their estate.