The NOK6100-CI is an internal battery only designed to replace OEM part number BL-4C. This li-ion Battery for the Nokia 5100, 6170, and 6100 is designed to fit internaly within your phone. Please note that Nokia did make a 5100/6100 series cell phone during the 90's which takes a different battery which secures to the back of the phone. Please view recommended accessories to view the older series of battery.
