Here is one more Wi-Fi detector T-shirt. The t-shirts are black & come with a choice of a green or blue Wi-Fi signal. The detector has five bars to determine the strength of 802.11b or 802.11g signals. It is powered by a couple of AAA batteries. The next time you go to a café, you don’t have to look for a Wi-Fi sign, just look at your own shirt. It is priced at $36 usd, choose from size ‘S’ to ‘XL’.