Chromecast is a small network device that runs a simplified version of Chrome OS, allowing users to stream video and audio content from smartphones, tablets and computers to their TV via a WiFi connection. By connecting to a TV's HDMI port, Chromecast displays content that is sent from other devices using apps that support the Chromecast platform, such as YouTube, Netflix and Google Play. Measuring only 2 inches long, Chromecast upgrades traditional TVs and monitors to smart TVs by adding network streaming capabilities.