Amazon.com: 40V 6000mAh Replacement for Ryobi 40v Battery, Replacement for 6.0Ah 40v Ryobi Battery OP4015 OP4026 OP40201 OP40261 OP4030 OP4040 OP40401 OP4050 OP40501 OP40601 Fit for All Ryobi 40V HP Series Tools :
RYOBI 40V Lithium-Ion 4.0 Ah Battery and Charger OP4040A-03 - The Home Depot
for 6.0Ah Ryobi 36V 40V Battery HP Li-ion BPL3626 BPL3626D BPL3640 BPL3640D | eBay
RYOBI 36V 5.0Ah 5.0 Ah 5Ah Hi-Tech Lithium Ion Battery Cordless BPL3650D2 NEW | eBay