A hammer drill contains a hammer clutch or a hammer-like mechanism which provides a circular rotation and a forward driving force. A hammer drill is capable of performing heavy-duty tasks, but it can also be used as a regular power drill.
A reversible drill can alter its rotations from a clockwise direction to a counter clockwise direction, a feature that makes it suitable for both drilling and driving.
Cordless tools/machines are suited to a variety of different situations, as you are not limited to only working in places with power sources nearby.
The height represents the vertical dimension of the product. We consider a smaller height better because it assures easy maneuverability.
The width represents the horizontal dimension of the product. We consider a smaller width better because it assures easy maneuverability.
A drill with a pistol grip handle is usually compact and lightweight, making the tool suitable for a large variety of apps and easy to use.