The center holes on the Jamb Shield are 3-1/2 inches apart. Each of the holes on the Jamb Shield are 2-inches long. The Jamb Shield will fit locks spaced from 4-1/2-inches to 21-1/2 inches apart. In the event your locks don't fit (which does not happen often), it is fine to file out an 1/8 to 1/4-inch to make it work. That will not void your warranty or cause any other issues. We use galvanealled steel so rusting is not an issue.