Flylinktech&reg; 18-Volt Extended Rechargeable Replacement Battery For Milkwaukee M18,48-11-1815,48-11-1820,48-11-1840(3.0 mAh Battery) M18 18v Battery for Milwaukee 48-11-1840 48-11-1815 48-11-1820 48-11-1840 M18 XC Red lithium 3.0 Ah extended run-time battery provides long run-time and battery life Fit for Milwaukee M18,2601,2610,2611,2620, 2630,2650,49-24-0171,48-11-1815,48-11-1820,48-11-1840 Built in high quality battery cells,No effect on the battery,Charging at any time Battery Storage - If you don't plan on using the Power Tool Battery for a month or more, store it in a clean, dry, cool place away from heat and metal objects. Ni-Cd, Ni-MH and Li-ion batteries will self-discharge during storage; remember to recharge the batteries before use