Mostafa Amaan of Valley4Techs explains in Arabic how to find out who is on your Wi-Fi and how to block them. The guide covers the router's device list, Wireless Network Watcher, Advanced IP Scanner and Angry IP Scanner. DeviceShelf is the fourth desktop tool in it.
He tested DeviceShelf on his own network. The section points out the Arabic interface, which he says is rare among network scanners, and that everything runs locally. He is also clear about who needs it: if you only want to see who is on your Wi-Fi, the free tools listed before it are enough.