Pursonic S750 Electric Toothbrush: - 1. 40,000 strokes/min. Thorough clean, even the hard to reach area. Remove 300% more plaques than a manual toothbrush. Long lasting time. For a full charge, it can last at least 30 days for normal use (brush twice each day). If it runs lower of power, the charging light will flash to remind you to get it charged. Only needs 4 hours to charge it. 3 modes for your choice: Clean, Soft, Massage. Clean mode for cleaning stains caused by coffee, smoke, tea; Soft mode for sensitive teeth; Massage mode for gums care.