ThinkGeek introduces a cool new black t-shirt with a useful functionality. The Wi-Fi Detector T-shirt as the name already implies shows the signal strength of available Wi-Fi hotspots near you.

The Wi-Fi Detector T-Shirt can detect 802.11b and 802.11g networks. The rings around the tower on the T-shirt logo light-up depending on the signal strength.

The Wi-Fi T-Shirt will sell for $29.99 when it begins shipping later this month from ThinkGeek.

You can use the “Email me when available link” on ThinkGeek to remind you about this great new black T-Shirt.

The Wi-Fi Detector T-Shirt is powered by 3 AAA batteries.