Know Thyself! Knowing where you stand is the first step toward reaching your destination. The simple, old-school tools in the Lightstuff Body Health Tool Kit help you monitor your key stats easily and accurately. The good news is that they are compact and do not even require batteries! The BMI Calculator Wheel shows you clearly if you are underweight, normal, a little overweight or obese. You can also use this tool to work out what weight you need to be to hit a certain BMI number. It is made of high-quality plastic for long-term use. The Body Fat Caliper is a simple, yet highly effective tool for checking your body fat level. This item comes with an illustrated instruction manual and body fat measurement charts for men and women. Electronic fat monitors are notoriously unreliable.