Replace the BIOS Battery on an IBM Thinkpad 600X Cheaply : 7 Steps - Instructables
IBM ThinkPad 600, IBM ThinkPad 600X, IBM ThinkPad 600E | IBM Laptop Battery
IBM ThinkPad 600X Battery:Replacement Battery For IBM ThinkPad 600X
Amazon.com: XPS Replacement Battery for IBM ThinkPad 1400i 2621-RR5, ThinkPad 2645, ThinkPad 600 PN 02K6486, 02K6489, 02K6502 : Health & Household
Amazon.com: Original Lenovo ThinkPad X60, X61, X60S, X61S Series Laptop battery 22++ (8 Cell, High Capacity 5200mAh/75W, 14.4V) 40Y7003 w/ one replacement Spacer & screws[NOT compatible with the X60 X61 Tablet PC