This little whizzer from Smart ID Technology, known as the "WiFi Trekker," represents the latest generation of Smart's low cost 802.11 detectors. The Trekker improves on the previous model (WFS-1) by auto-scanning for networks—press the button a couple times, and when a network is discovered, the Trekker lights up and buzzes at you. Plus it's cooler looking.
Smart ID Homepage [SmartID]
SMART ID's WiFi detector [Gizmodo]