Homedepot offers RYOBI ONE+ 18V 3.0 Ah LITHIUM+ HP Batteries (6-Pack) P191K6 - The Home Depot for $199 free shipping.

Product Description:
Enter the RYOBI 18V ONE+ System with the 18V ONE+ 3.0 Ah LITHIUM+ HP Batteries (6-Pack). These batteries feature electronics to allow you to extend tool performance with added capacity to all 18V ONE+