Generic Upgraded Version: 800 mAh 3.7v Li-ion Electric Toothbrush Replacement Battery Compatible with Philips HX9340 HX6930 HX6750 HX65
Amazon.com : Upgraded 800mAh 3.7v Li-ion Electric Toothbrush Replacement Battery compatible with Philips HX9360 HX6340 HX6610 HX6970 HX6511 HX6711 with pins to fit circuit board and extra rubber seal value 6.99USD :
Philips Sonicare ProtectiveClean 6100 HX6871/49 Whitening Rechargeable Electric Toothbrush with Pressure Sensor and Intensity Settings, Navy Blue - Walmart.com