Measure your fitness or progress with the Sequoia Fitness TrimCal 4000 Skinfold Body Fat Caliper. This device measures the thickness of a fold of skin with its underlying layer of fat. This helps you or your fitness mentor chart an exercise or diet program that's tailor-fit to your needs. This skinfold caliper can measure up to 80mm of thickness. Its spring-loaded arm's design assures reproducible results. The package includes easy-to-follow instructions, plus a fat chart for male and female measurements.