Location of the BIOS battery on a Toshiba Portege z20t - Super User
Amazon.com: Synergy Digital CMOS/BIOS Battery, Works with Toshiba Satellite Pro S300-EZ1511 CMOS/BIOS, (Ni-MH, 2.4V, 20 mAh) Ultra High Capacity Battery : Electronics
CMOS Battery Repair | Toshiba Satellite pro 4200 series - YouTube