If you have dead WiFi spots in your house or your home network speed keeps dropping out, consider getting a simultaneous dual band wireless range extender such as the Pix Link AC750M WiFi repeater.
With a simultaneous dual band wireless range extender, you essentially get a device that boosts two wireless frequencies (2.4 GHz and 5GHz) in one single box at the same time. Simultaneous dual band means that the dual band repeater has the ability to repeat both 2.4 GHz and 5GHz wireless bands simultaneously (as opposed to a dual band repeater that only repeats one wireless band at a time).
You can you use a dual-band wifi extender with a single band router, though it's a good idea upgrading to a dual band router that can handle both 2.4 GHz and 5GHz wireless bands to maximize your network connection potential.
Pix Link AC750M's simultaneous dual band wireless range extender features two external antennas that help speed up the connection up to 750 Mbps by reducing interference and providing a more reliable connection.
The AC750M WiFi repeater is also backwards compatible with 802.11 b/g/n and AC standard, and can be used also as a wireless access point and as a router.

The wireless access point feature is quite handy if you have a non-wireless-enabled router and you want to make the router wireless-enabled.
Pix Link's simultaneous dual band is easy to set up as a wireless range extender. Simply push the WPS button on the repeater and your router, and the repeater will be using the same SSID as your router.