Optimal Plaque Control Toothbrush Heads, 3 Brush Heads Boxing Soups and More They re also backed Soups and More Large pads on back for extra comfort makes carrying heavier loads more comfortable on stress areas of the back A fresh brush head every 3 months maximizes the effectiveness of Philips unique Sonicate technology Use with a Philips Sonicate brush Sync(TM) compatible handle (Diamond Clean Smart or protective Clean) to unlock Smart features brush Sync mode pairing triggers your handle to select optimal mode and intensity level for exceptional plaque removal (certain models only) brush Sync replacement technology tracks how often and how hard you brush and will notify you when it is time to replace your brush head