@jarred77 

The kits are not sold individually. You will need to purchase another kit in order to add them in your existing powerline network. You do not have to wire another adapter to the router, only one device is wired, and the rest of the powerline adapters are placed around your residence.

If you are looking to add adapters to wire to the computer, you do not needs another wireless kit, you can get the wired only such as the TL-PA7010 KIT. You will have two wired only adapters to place anywhere.

Thank you very much for the advice

@Tony 

Do you know if a TL-WPA4220 will pair with a TL-WPA7510 kit?  I have the 7510 kit installed and running but would like to put a 4220 in another section of the house if possible.

Thanks for any help you can provide.

Sam

@Tony This is crazy.  I bought two kits originally, as I wanted two Wi-Fi extenders, so already have one 'spare' (=unused, wasted) base unit.  Now I require another Powerline Wi-Fi extender for my shed and you say the only way is to buy yet another complete kit and have 2 wasted base units.

Can't TP-link look at their sales procedures, and sell just the Wi-Fi extender, as phone companies do.  I bought a phone system with a base answerphone and single remote unit.  Then wanted to extend and could buy either a single, two, or three remote units without having to buy another base unit.

@Robert-E 

Agreed, would really like to see them offer this.  I would buy two more extenders one for a hard to reach area downstairs in my home and another for my shop.  But buying two more kits seems like a horrible waste of money.