ioT device connection requiring 2.4 Ghz

I purchased a Feit Electric Smart Water Sensor that requires a 2.4 Ghz Wi-Fi network.  We have an Xfinity Technicolor XB8 Gateway at home.  I cannot get the sensor to connect to WiFi.  Is there an extender available that can be configured to only extend the 2.4 Ghz band so that I can get the sensor to work?

Thanks.