>>> Type: LAN Ethernet Adapter kit

Fitment:
Fit for Fire TV Stick 3/2nd Generation 2AE6S-0948
Fit for 4K Firesticks.
(NOT Fit for Fire stick's 1st Generation 2ABDU-0509)

Interface: USB 2.0
Ethernet: Transmission Speed 10/100 Mbps
Color: Black

This is a must-have accessory if you're having any kind of buffering or streaming problems.
Feature: Plug and play, no need to configure any settings.

This device is designed to give you a better internet connection. WiFi can be fast but it also can also slow down during peak times, it transmits in waves (fast and slow). With a wired connection this removes this cause of buffering by giving you a steady internet stream.

If you have one and are not sure what generation you have, unplug it from the TV and look at the bottom of the stick and look for these numbers (the writing is very small)

Buffing or lagging may not be eliminated completely as buffering is caused by more than 1 thing. If you are using a streaming service to watch TV then you may still buffer if that service is to slow.

Here are a few suggestions on how to get the TV Box to connect to the internet with the Ethernet:
Remove the Power Cable from the TV Box.
Connect the Ethernet cable to the TV Box, and the other end to your router.
Power the TV Box back on.
This will usually correct the issue of the TV Box connecting to the internet over Ethernet.

You Can Also Check the Settings:
Connect one end of an Ethernet cable to you TV Box and the other end to your router.
In the Screen go to Home screen, select Settings > System > Network > Wired. This Should select the wired network as you primary internet connection.

If this does not work
then you have to do a factory reset. after that it will connect automatically with your hard wire