Re-Celling an Extended Slice Battery - Thinkpads Forum
Lenovo ThinkPad X220 Review - Notebook Reviews by MobileTechReview
Just bought a quirky x220 slice battery. Looks exactly like a 19+, but says 20+. Works completely fine with 1% wear. Does anyone know what it might be? : r/thinkpad
ThinkPad slice battery for X220 / X230 - YouTube
ThinkPad X220 versus ThinkPad X230 with 19+ battery slice | Flickr
Amazon.com: Lenovo 0A36307 ThinkPad 9 Cell Extended Life Battery 44++ for Lenovo ThinkPad X220, X230 Models Only. (Caution: Not for X220 Tablet, X230 Tablet Models) : Electronics
Lenovo ThinkPad X220 Hands On, Details, Specs And Video