The HIF also tests, evaluates, repairs, calibrates, and develops hydrologic equipment and instruments. Calibrates and repairs over 8,800 items in a regional Test, Measurement, and Diagnostic Equipment Laboratory. Hampden also calibrates hardness testers and services, and calibrates ozone cabinets. Relating the observable quantity to the calculated cluster mass profile calibrates the mean mass-observable relation. The Blue Wool Scale measures and calibrates the permanence of colouring dyes. It also calibrates the national standards of weights and measures. Also, each list calibrates their Elo via a different method. The nuts were radiocarbon dated to , which calibrates to .