Two batteries for less than the price of one. Shows to be clearance available online.
RYOBI 18-Volt ONE+ Lithium-Ion LITHIUM+ HP 4.0 Ah High Capacity Battery (2-Pack)
https://www.homedepot.c
Non-HP version is same price:
RYOBI 18-Volt ONE+ Lithium-Ion 4.0 Ah High Capacity Battery (2-Pack)
https://www.homedepot.c