In order to build a rock hard body, you need to exercise and watch what you get. To get a good six-pack like top athletes, you need to reduce your fat. The Tanita SR-903 is a subcutaneous fat analyzer that can help you stay on track. It measures how much fat lies under your skin. It uses 4 electrodes to get the job done.
The Tanita SR-903 Subcutaneous Fat Analyzer has a measuring range of 0.3 to 5cm. It weighs only 91g and has a compact design. You can find out more about it here.