The most direct, simple and accurate method for estimating leanness to fatness is measuring the thickness of skinfolds with constant-tension calipers. Accurate to plus or minus 1mm. Tips pivot automatically for parallel measurement. It has an easy to read scale up to 60 mm. All critical pivot points utilize low friction bearings. Spring loaded levers provide a substantially constant standard pressure of 10 gm./sq. mm. Lange calipers come with a hard shell case and instruction book.