Does the hammer drill work on concrete?

Yes. It has a hammer mode for light masonry drilling in brick and concrete. For heavy concrete coring, a corded SDS rotary hammer is the better tool.

How many batteries come in the kit?

The kit ships with one 20V MAX battery and a charger. Buyers who work long days usually add a second pack.

Is this kit worth it over a compact 12V set?

If you drill masonry or drive large fasteners, the extra torque and hammer mode justify the size. For cabinet work and light assembly, a compact 12V kit is easier to handle.

Can I use my existing DeWalt 20V MAX batteries?

Yes. Both tools run on DeWalt's 20V MAX batteries, so existing packs and chargers work with them.

What is included in the box?

The hammer drill, impact driver, one 20V MAX battery, a charger and a contractor bag.

How does it compare with Milwaukee's Fuel combo kits?

Both are brushless pro-grade kits. Milwaukee's Fuel line is often cited for compact size and its own battery platform; DeWalt competes on torque and the breadth of its 20V MAX lineup.