Amazon.com : OralClass Replacement Toothbrush Heads Compatible with Sonicare Electric Toothbrushes, Medium to Soft Electric Brush Head Refills Fit for Philips Sonic Care Click on Handles, 8 Pack : Health & Household
Best Buy: Philips Sonicare C1 ProResults Standard Replacement Toothbrush Heads (3-Pack) White HX6013/63