Hikoki BCL715G 7.2v Li-Ion Batteries (for NR90) are available for next day delivery from Brighton Tools
This battery is for use only with the Lithium-Ion version of the NR90. Use with other tools may cause the tool not to operate correctly.
Be sure to remove the battery when the tool is not in use, If the battery is attached to the nailer for 12 hours or more, the battery's output will be automatically shut off due to the built in Auto Power OFF feature for the purpose of reducing battery consumption. In this event, the tool will not operate when the trigger is pulled, but this is not a malfunction.
In the event of Auto Power OFF, to make the tool usable again, detach and reattach the battery.
If the tool still doesn't operate, the battery is likely empty and will need re-charging.