The scales are incredibly accurate and consistently so; five attempts in a row show the same weight. Taking on food/drink and disposing of body waste affects your weight and these scales will pick this up. The unit is very simple and quick to pair with my V800 and iPhone app, which offer various feedback/tracking data of their own. However, the web app is where it's at. After pairing to my V800 and then synching to Polar Flow, a new section called 'Balance' appears in the diary tab of the Polar Flow web service. It's well presented, very detailed and not overly complicated. After setting a weight loss target and time period the web app will produce recommended levels of activity each day, these keep you motivated and help you achieve your goal. If you wear an activity tracker (V800, M400, Loop) you can choose to display an activity bar below the time and date on the front screen of the display, so you always have that reminder there. I have been very impressed with this bit of kit.