Portable electronics usually need a battery, but some of them aren't meant for on-the-go operation, only as a means to quickly set up a network when arriving at a destination.
The new Satechi mini wireless router is definitely one of the latter.
Capable of creating a 802.11b/g/n Wi-Fi network with a throughout of 300 Mbps, it easily goes into power sockets and stays there.
Two Ethernet ports are present as well, on the lower side, and there is even support for WPS security and WLAN security with WPA2, WPA, and WEP (128/64) capability.
To enable the encrypted operation mode, only one button needs to be pressed. There is QoS functionality, for high-quality VoIP and multimedia streaming.
Satechi sells the mini router, which can also behave as an access point and universal repeater, for $39.99 / 29.93 Euro.