Product details:

You get two batteries in each DeWalt lithium-ion battery pack, so you can swap out a charged battery with a low battery and keep working. The XR models deliver up to 60 percent longer running times than the standard 20V MAX batteries. This 20V MAX lithium battery resists forming a "memory", so you can put it on the charger at the end of a long day instead of waiting for it to fully drain before you recharge it. These batteries weigh just 1.4 pounds, which contributes only slightly to the overall weight of your tools and allows you to work with reduced strain and fatigue.