Amazon offers the Oral-B Professional Floss Action Replacement Brush Head 3-Pack, model no. EB25-3, for $15. Add it to your cart via Subscribe & Save to drop it to $14.25 and bag free shipping. That's $2 under our January mention and the lowest total price we could find now by $5. Compatible with Oral-B Professional Care and Oral-B AdvancePower electric toothbrushes, they purport to remove 100% more plaque than manual toothbrushes.
Be sure to cancel Subscribe & Save after your order ships to avoid being charged for subsequent orders.