20V 4AH MAXIMUM POWER- Enjoy a high capacity battery for longer run time and stable performance, ideal for intensive work with your wireless tools from Energizer.LONG BATTERY LIFE & DURABILITY- High quality lithium-ion battery with exceptional endurance, without memory effect or premature charge loss for long lasting performance.Improved reliability and safety- Advanced protection against overload, overheating and short circuits for worry-free work, even on demanding construction sites.100% Compatible with 25 Energizer Tools- Perfect for your drills, screwdrivers, grinders, saws and more. Switch tools with one click for maximum flexibility.Fast and efficient charging- Optimized charging time to minimize interruptions. Combine it with an Energizer fast charger for even more efficiency and productivity!