Amazon.com: Replacement Battery Part No.3731,3738 for Oral-B Professional Care 8000,Professional Care 8300,Professional Care 8500,Professional Care 9500,Triumph 4000,Triumph 5000,Triumph 9000,9400,9500,9900 : Health & Household
Braun Oral-B Professional Care 9900 Triumph Ni-MH battery Replacement - iFixit Repair Guide