Review on Enhance Wi-Fi Range and Speed with AT&T Airties Air 4921 Smart Wi-Fi Extender - 1600Mbps Dual Band 3x3 802.11ac by Ryan Hawkins

I couldn't extend the 2.4GHz signal or the guest channel. Setup seemed easy, but troubleshooting put the initial setup time to shame. 5G signal within 20 feet of the power strip was strong but dropped quickly; it was still better than the TP-Link extension it replaced. I found it took a long time to switch from the router to the power strip; I had to toggle Wi-Fi on and off on my device to switch instantly. Update: After about a week I found the grid was working as intended with almost no issues. Apparently there is some sort of customization process going on, either with my devices or with an extension cord. In any case, it works the same as the previous one, 5G and 2.4G are available and sufficiently strong signals, so I've increased my rating.