Quad band mesh routers ensure the highest stability and a large range via 4 frequencies. They use a 2.4GHz band with a large range. The 6GHz band is used for your fastest devices. The 5GHz band is the most used. A second 5GHz band ensures the connection between the mesh stations. So the first 5GHz band is still available for your most important devices and you won't lose speed due to a long distance between your mesh stations.