Vertex Standard FNB-V129LI (AAJ63X001) battery is the high capacity battery for VX-821, VX-824 or VX-829 and a direct replacement for FNB-V92LI (not FNB-V92LIIS, read more below). This battery also requires an updated charger, VAC-UNI (H), as the old CD-53 charger is not compatible with this battery.
Updated Charger Required: The old FNB-V92LI used the CD-53 charger. CD-53 charger is not compatible with this battery and therefore you will need a new charger. The correct charger for this battery is Motorola VAC-UNI (H) available here.
FNB-V92LIIS Notes: FNB-V92LIIS is a special edition of the original FNB-V92 but for “IS” (intrinsic safety) models of this radio only. If you have a FNB-V92LIIS and need a replacement, you should see the Vertex Standard FNB-V129LIIS, not this battery.