The 20V MAX* 4 Ah lithium-ion battery features no memory loss and minimal self-discharge so the batteries are ready when needed. These batteries deliver maximum runtime for heavy duty applications. They power all Porter-Cable® 20V MAX* power tools. Porter-Cable® 20V MAX* MATRIX™ Cordless Tool Battery, Rechargeable, Bare Tool, Lithium-Ion Battery, 4 Ah Battery, 20 VDC Charge, For Use With: All Porter-Cable® 20 V MAX* Power Tools