466296-001 - 55Whr 10.8V 6-Cell Battery for HP Elitebook 8440p 8440w Probook 6550b 6555b - CPU Medics
eReplacements Compatible 9 cell 7800 mAh battery for HP Probook 6450b 6545b 6550b 6555b For Notebook Battery Rechargeable 7800 mAh 11.1 V DC - Office Depot