8-Pack is a 1 Year Supply For 2 People – Color Coded Rings to Remind 2 Users to Change Brush Head Every Season. Features +29% More Cleaning Bristles and New Trim Pattern for Improved Tooth Cupping. Dentists recommend changing your brush head every 3 months Indicator bristles fade half-way to signal it is time to change your brush head. Fits: Oral-B Professional Care Smart Series, Triumph, Professional Care Series, Vitality, Precision Clean, Dual Clean, Floss Action, ProWhite, Pro-Health Battery Powered, AdvancePower Series. Made in Germany.