Miss. Code Ann. § 75-31-211

If a tank is designed for use with a surface gauge, a substantial or rigid surface gauge bracket or other suitable supporting elements for positioning the surface gauge shall be provided. A surface gauge and its bracket or other supporting elements shall be so constructed that whenever the gauge assembly is placed in engagement with the bracket or supports, the indicator, if not permanently mounted on the tank, will automatically seat itself in correct operating position, and the graduated element will be vertically positioned and will be securely held at any height to which it may be manually set.