Roku is getting into an Internet video-streaming stick fight with Google's Chromecast.

Like the similarly shaped Chromecast, Roku's thumb-sized device plugs into the HDMI port of a television and feeds Internet video through a Wi-Fi connection.

The Roku device, announced Tuesday, sells for $50 compared with $35 for the Chromecast. The low price and Google brand cachet have made Chromecast popular since its release last summer. Google hasn't divulged Chromecast sales, but it's the second-most popular electronics item on Amazon.com.

Some of Chromecast's sales may have come at the expense of Roku's set-top boxes for showing Internet video. The latest box, the Roku 3, sells for $99.

Roku Inc. says it has sold more than 8 million video-streaming devices since its first box hit the market nearly six years ago.