Includes the Fat Track Digital Skinfold Calber and Myo Tape.The principle of skinfold calipers is to estimate body fat percentage by measuring the thickness of a fold of skin with its underlying layer of fat at a key measuring site. Research has shown that within the range of 15-40 percentage body fat, skinfold method has almost the same accuracy as underwater weighting. In ranges under 15 percent, the skinfold method is more accurate than the underwater method.