The Hyper Tough 12V Max* 4.0Ah Lithium-Ion Battery is the perfect upgrade for your Hyper Tough Power Tools. This 12V Max* 4.0Ah lithium battery pack delivers steady consistent power for a long consistent charge and battery life. Lithium-Ion Batteries have a high energy density which provides a longer discharge time and provides consistent power through the charged cycle. Unlike NI-Cad batteries which slow down as energy is depleted, these Lithium-Ion batteries run at full strength until all energy is expended. Once charged Lithium-Ion batteries also have a longer shelf life and will not lose power when not in use. Standard 3 to 5-hour chargers and 1-hour fast chargers are available separately. The Hyper Tough 12V Max* 4.0Ah Battery is compatible with all Hyper Tough 12V chargers and Hyper Tough tools and outdoor power equipment, get yours today!