New Panasonic CF-VZSU0KW CF-54 2nd Bay Battery, Li-ion Rechargeable Battery Packs
Panasonic Toughbook CF-54 - Tough Outlet
Amazon.com: PANASONIC TOUGHBOOK 55 FZ-55 FZ-VZSU1HU Standard Battery for FZ-55 Mk1. Can be Used as a Replacement for The Main Battery or as an Optional Second Battery in The Front : Electronics