Recommended in Body-for-LIFE and endorsed by the World Natural Bodybuilding Federation, Accu-Measure personal Body Fat Testers have gold standard accuracy to within 1.1% of underwater weighing results! A clinical study published in the Journal of Strength & Conditioning Research by the National Strength & Conditioning association sited the following key findings: •Self-testing of % body fat with the Accu-Measure was as accurate as results from multi-site measurements and calculations taken by an experienced clinical investigator using a Lange caliper. • % body fat calculations with the Accu-Measure were within 1.1 percentage points of underwater weighing results. Features: Accurate - This registered medical device is clinically proven to be more accurate than lengthy, complicated methods costing thousands of dollars.