PANASONIC EY9L54B32 18V 50AH LIION SLIMLINE BATTERY Longer runtime than the 30 Ah version Ultra light & compact Slimline Battery Compatible with Panasonic 18v Power Tools Innovative pbattery cells & single parallel design for increased lifespan Overdischarge prevention sensor Battery overheat protection sensor OPS Individual monitoring of cell voltage Heat resistance layer HRL Technology Voltage 18v