A cordless rotary hammer drill is a powerful handheld tool combining hammering action with rotary drilling, driven by a battery (usually a high-capacity lithium-ion pack) rather than mains power. It's designed for drilling into tough materials like concrete, masonry, stone, and sometimes brick, while offering the freedom of mobility and ease of use without cords. The hammer mechanism delivers percussive blows as the bit spins, helping break up hard surfaces and drive the bit into material more efficiently. Often these tools also have auxiliary handle(s), variable speed, mode selectors (drill, hammer drill, chisel), and are built ruggedly for job-site durability. They're especially useful for overhead work, remote jobsites, or where access to power is limited.