Latest technology. Ego batteries have been designed to ensure you get the best from your battery equipment. The ARC patented design allows the battery to work every cell without it overheating as it dissipates heat more effectively. The batteries are always exterior mounted on the power tools and not encased to ensure that the battery stays cooler for longer lasting power, to keep them safe and sound the electronics are protected from dust and moisture by a resin coating and in a robust cast that absorbs shocks and vibrations. With BA4200E 7.5Ah battery has fast recharge time with the rapid charger of just 60 minutes, it allows you to get back to work quickly.