Hotop 24 Volt C Wire Adapter for Smart Thermostat, UL Listed 16.5ft Long Power Connector C Wire for All Versions of Smart Thermostat Compatible with Nest, Honeywell, Ecobee, Wyze, Sensi - - Amazon.com
Old thermostat has wire 1, 2 & 3. Which smart thermostat is compatible? : r/electrical
MoesGo Programmable WiFi Smart Thermostat for Home, No C-Wire Required by C- Wire Adapter, with Zone Remote Sensor, Remote Control Tuya/Smart Life, Compatible with Alexa and Google Assistant, 24VAC - - Amazon.com
Nest Wiring Diagram How To Install C Wire or Common Wire - YouTube