Thermostat Wire, Indoor/Outdoor Sun Resistant, Brown — Primus Cable
Buryeah Thermostat Wire Bell Wire Solid Copper Cable 18 Gauge ETL Electrical Wire, Power Circuit Cable Moisture, Heat and UV Resistant for Low Voltage Applications Use (18/2,25 ft): Amazon.com: Tools & Home
Southwire 18 / 5 Solid Thermostat Wire (By-the-foot) in the Thermostat Wire department at Lowes.com
Thermostat Wire 18/7 - Brown - Solid Copper 18 Gauge, 7 Conductor - CL – THE CIMPLE CO
What is the wire gauge for a thermostat connection? - Quora