BLACK+DECKER LB2X4020-OPE 20V 4.0Ah Lithium Ion Battery Pack BLACK+DECKER's highest capacity battery pack for the 20v MAX system of tools The 20v MAX 4.0 ah pack has 2x the capacity as the LBXR2020 2 Year Warranty BLACK+DECKER's highest capacity battery pack for the 20v Max system of tools The 20v Max 4.0 ah pack has 2x the capacity as the LBXR2020 2 Year Warranty