28 volt Lithium-Ion battery packs power the entire Milwaukee V28™ System of power tools. The V28™ Lithium-Ion battery pack offers up to twice the run-time of an 18V NiCd or NiMH pack and is actually lighter than 18V NiCd and NiMH packs! Lithium-Ion technology allows consistent fade-free power - meaning the first cut is as powerful as the last. V28™ Lithium-Ion battery packs will never develop a memory and can be charged at any time regardless of the pack's current charge level! Press the 'fuel gauge' button and LED indicators display remaining charge left in the pack, providing an ideal way to check the state of the pack before you climb onto a roof or up a ladder.