Works amazing on:

For 2nd Gen fire sticks
For 3rd Generation Fire TV (pendant)
For 4K Firesticks.

(NOT FIT FOR 1st Generation Fire stick's)

If you are not sure what generation you have, unplug it from the TV. look at the bottom of the stick and look for these numbers (the writing is very small)
1st-gen = 2ABDU-0509 (not compatible) 2nd-gen = 2AE6S-0948 (works GREAT!)

Product Specification

Type: LAN Ethernet Adapter For Fire Stick
Suitable: For Fire TV Stick 3/2nd Generation
Interface: USB 2.0
Ethernet Transmission Speed: 10/100 Mbps
Color: Black

INTERNET SPEED - 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.

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

if you have any issues

Here are a few suggestions on how to get the TV Box to connect to the internet with the Ethernet.

Easiest First: 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.

If this does not work then...You Can Also Check the Settings:

Connect one end of an Ethernet cable to TV Box and the other end to your router.
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.