The Western Digital My Pasport Wireless is a portable Hard Disk Drive and Wifi Access Point which runs on Battery and serves as wireless file server on the go.
Mobile WLAN Hotspot
My inital setup was in a WLAN network at home in which all my devices are in the same network within the WD My Passport shares the files on it to all devices on the network. The mobile harddisk has a built in battery which according to WD runs about 6h, unfortunately I did not test the battery life in real world conditions.
The Drive can connect to a Google Chromecast, but I was not really successfull to play any video through the WD My Cloud Android App. One way of playing movies through the WD My Passport drive on the Google Chromecast is to access the movie files directly on the drive with the ES File Explorer app which directly streams it on the Chromecast stick.