A drill with a pistol grip handle is usually compact and lightweight, making the tool suitable for a large variety of applications and easy to use.
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 chuck holds the drill bits or other rotary tools and its diameter determines the types of bits and tools that the drill can use. A larger chuck is compatible with a wider range of bits and tools.
A keyless chuck drill enables you to change out drill bits rapidly without having to use any special keys.
A tool/machine with a higher voltage produces more power.
A drill with variable speed allows you to switch between low and high speeds, giving you the possibility to take on a wider range of tasks.
Higher speeds work better for drilling holes in certain types of material, such as steel, aluminium, concrete, etc. The drill speed is measured in rotations per minute (rpm) when the drill has no-load.