5) Pack Philips Sonicare C1 Simply Clean Brush Heads 2 Pk X 5 = 10 Head Total | eBay
Amazon.com : Toothbrush Replacement Heads Compatible with Philips Sonicare, Medium to Soft Electric Brush Head Refills for Sonic Care DiamondClean C1 C2 C3 G2 G3 W2 W3 4100 5100 6100 etc, 8