I stayed in the mountains during summer vacation, but there was no internet access, and I was relying on a single 4G antenna. I bought this out of desperation, but I couldn't find a way to install it at a high location during the trip, so I gave up on setting it up. It's almost new, as I only opened the box, took out the product, and then put it away. Comments and questions are welcome. Note: Please confirm the frequency bands of your mobile phone before purchasing. Brand/Manufacturer: ANNTLENT Function: Improves call quality and internet speed. Multiple users can use it simultaneously. Automatically adjusts to the maximum radio wave performance. Supported frequencies: Band 28, Band 26, Band 8, Band 3, and Band 1. Band 28 Uplink: 703～733MHz Downlink: 758～788MHz. Band 26 Uplink: 814～849MHz Downlink: 859～894MHz. Band 8 Uplink: 890～915MHz Downlink: 935～960MHz. Band 3 Uplink: 1710～1785MHz Downlink: 1805～1880MHz. Band 1 Uplink: 1920～1980MHz Downlink: 2110～2170MHz.