The 40V 4.0Ah Battery is the extended run time pack in our 40V range. By using the 4.0Ah Battery you get twice the run time than the standard 2.0Ah battery. This helps to get more power, performance and satisfaction from your Greenworks tools. Our 40V products are powered by our highly efficient lithium-ion batteries, built for effortless performance and better results. Our batteries are designed to offer maximum simplicity, convenience and versatility. With a range of run time options, they are quick to recharge and even quicker to switch. Zero fumes, no maintenance, no hassle. 40V products are ideally suited to jobs in medium sized and family orientated gardens.