This is a Vintage Mexican Sterling Silver Bangle in a Twist Rope or Braid Style.
It measures 2 5/8" across the inside and is just a little under 1/4" wide. It is marked MEXICO STERLING 925; it is in Nice Vintage Condition, it looks like it was sized at some point. It weighs about 14-15 Grams on my little postal scale.
Sterling Silver Mexican Bangle Bracelet