Amazon offers the DeWalt Battery Adapter Kit for $132.95. At final checkout, it falls to $112.95. With free shipping, that's the lowest price we could find by $36, although we saw it for a buck less last week. It includes two 20-volt Max XR lithium-ion batteries and a 20-volt charger. Deal ends June 18.

Update: The price has dropped to $129 before discount, $109 after.