It's a WiFi to Ethernet bridge. There are many out there so I'll link one and stop there.
OK, there are such devices but that hidden SSID doesn't play well with a lot of devices. We saw a lot of complaints so I won't debate why it's like that. It's not as if adds to security.
I provide a wireless network with a hidden SSID for my residents. I have a resident who has a Arris Surfboard SBG6580 cable modem connecting all his devices to a cable provider. He now wants to switch everything to my wireless network. Not all his devices are wireless capable. How can I connect his existing "network" to my wireless network? Do I need a wireless bridge or a wireless access point?