Flashlight

The flashlight is an item that is always in the player's inventory and is attached to every weapon the player can obtain. You cannot drop it, but you can turn it on and off, which makes a clicking sound. It allows the player to see in dark areas when exploring for items and weapons. It allows the player to scout out such areas for groups of Common Infected, and spot Special Infected much easier. Also, the flashlight is attached in a fixed point on your weapon which means that when meleeing, changing weapon and reloading you lose the benefit of the light as your weapon moves and changes angle.

The flashlight is a sure-fire way to disturb the witch. Shining it on her will disturb her much quickly than standing near her, so you should aim your crosshair away from her, or turn it off altogether. Also, idle common infected are disturbed quicker when you shine your flashlight on them.

Trivia

 * You can still somehow use the flashlight even when wielding items such as pills, and gas can, even when they do not have one attached to them.
 * Even though the common tactic is to switch off your flashlights when a witch is nearby, it is usually unnecessary as the witch is only disturbed by the light when you aim it directly at her.
 * You cannot see another survivor's flashlight area, but you can tell they whether they have their light on or off.