The 28-Volt Lithium-Ion battery pack powers the entire Milwaukee® V28™ System of power tools. It s lighter and offers up to twice the run-time of an 18-Volt NiCd or NiMH pack! Never develops a memory and can be charged at any time regardless of the packs current charge level. Press the ‘fuel gauge’ button and LED indicators display the remaining charge left in the pack, providing an ideal ay to check the batteries state.