Festool 495479 Replacement Battery for T12+3 Cordless Drill, 10.8 Volt, 2.6 Ah Li-Ion Energy density of lithium-ion is typically twice that of NiCd batteries Allows portable drill usage, easy to store and use Virtually no memory effect with Li-ion batteries No scheduled cycling required to prolong the battery's life Self-discharge is less than half compared to NiCd