The speed broadcast by the LED with Wi-Fi Extender is highly dependent on a variety of factors; primarily, these factors are: the bandwidth (speed) of your router at the location of the LED with Wi-Fi Extender, the distance from your router to the LED with Wi-Fi Extender, and physical obstacles between your router and the LED with Wi-Fi Extender.
Like all Wi-Fi extenders, the LED with Wi-Fi Extender will re-broadcast your Wi-Fi at half speed. The advantage of this is to get some Wi-Fi into an area that previous lacked Wi-Fi.
For example:
Your router broadcasts 50 Mbps of download and 10 Mbps of upload while you are right next to the router; 25 feet away, the bandwidth drops to 25 Mbps of download and 5 Mbps of upload. If the LED with Wi-Fi Extender is setup 25 feet away from the router, the Sengled LED with Wi-Fi Extender will rebroadcast the WiFi at 12.5 Mbps of download speed and 2.5 Mbps of upload speed; this is, of course the speed that will be next to the LED with Wi-Fi Extender.
Wi-Fi, like all wireless signals, will get weaker the further away it gets from the source.