The Apple-developed Airtag uses the Apple crowdsourced Find my network tool.
Using UWB (ultra-wideband) technology synched with a built-in U1 chip. Airtag is compatible with devices running iOS/iPad OS 14.5 or later. Almost any iPhone, iPad, or iPod Touch device will work.
The Apple AirTag runs on Bluetooth technology. And it needs to be within 30 feet of a phone in order to work. Tile technology operates the same way.