Input devices capture information from the external environment and translate it into a format that can be processed by computers. Common input devices include keyboards, pointing devices like mice and trackballs, game controllers, scanners, styluses, microphones, digital cameras, and web cams. Keyboards are the most common input device and come in both wired and wireless varieties. Pointing devices are mainly used to choose and enter commands. Scanners are used to digitize images and documents. Microphones input audio and come in desktop, headset, and directional varieties. Digital cameras capture still images and video.