NeweggBusiness - TP-Link AV600 Powerline WiFi Extender - N300 WiFi, Add-on Single Adapter, Ethernet over Powerline, Plug & Play, Compatible with all TP-Link powerline adapters with different speed (TL-WPA4220)
tp-link AV600 Powerline Wi-Fi Extender User Manual - Manuals+
Amazon.com: TP-Link Powerline WiFi Extender - Powerline Adapter with WiFi, WiFi Booster, Plug & Play, Power Saving, Ethernet over Power, Expand both Wired and WiFi Connections, AV600 (TL-WPA4220 KIT)