The most direct, simple and accurate method for estimating leaness-fatness is measuring the thickness of skinfolds by constant-tension calipers. Features: Accuracy to + or - 1mm, tips pivot automatically for parallel measurement, Easy to read scale up to 60 mm, all critical pivot points utilize low friction bearings, spring loaded leavers provide a substantially constant standard pressure of 10 gm./sq. mm, lange Calipers come with a hard shell case and instruction book.