The 10.0 Ah ARC Lithium™ Battery is fully equipped with an upgraded fuel gauge. The built-in indicator lights lets you see how much run time you have left. With 5 segments wrapping the power button, you can now see how much battery power you have left in 20% increments. The ARC Lithium™ battery technology is the industry’s most advanced; equipped with patented Keep Cool Cell Technology; which keeps the cells cool and prolongs the life of the battery. (Please note the 10Ah battery, BA5600T does not fit into the 49cm mower LM2001E)