![Amazon.com: Syston 18/2 Thermostat Doorbell HAVC Heating Control Cable Wire, 18 AWG 2 Conductors100% Solid Copper Conductors CL3R/FT4/CMR Riser-Rated, UV Resistant RoHS for Low Voltage Applications Use : Tools & Home Improvement Amazon.com: Syston 18/2 Thermostat Doorbell HAVC Heating Control Cable Wire, 18 AWG 2 Conductors100% Solid Copper Conductors CL3R/FT4/CMR Riser-Rated, UV Resistant RoHS for Low Voltage Applications Use : Tools & Home Improvement](https://m.media-amazon.com/images/S/aplus-media-library-service-media/2ff2e736-5131-47d4-9a80-d5bb03fbe259.__CR0,0,600,450_PT0_SX600_V1___.jpg)
Amazon.com: Syston 18/2 Thermostat Doorbell HAVC Heating Control Cable Wire, 18 AWG 2 Conductors100% Solid Copper Conductors CL3R/FT4/CMR Riser-Rated, UV Resistant RoHS for Low Voltage Applications Use : Tools & Home Improvement
![Southwire 50-ft 18 / 7 Solid Thermostat Wire (By-the-roll) in the Thermostat Wire department at Lowes.com Southwire 50-ft 18 / 7 Solid Thermostat Wire (By-the-roll) in the Thermostat Wire department at Lowes.com](https://mobileimages.lowes.com/productimages/d0ab1176-ea02-4acf-9f34-826927a39cff/00468982.jpg)
Southwire 50-ft 18 / 7 Solid Thermostat Wire (By-the-roll) in the Thermostat Wire department at Lowes.com
![wiring - How to add Thermostat C Wire to Furnace TH/TR and Transformer - Home Improvement Stack Exchange wiring - How to add Thermostat C Wire to Furnace TH/TR and Transformer - Home Improvement Stack Exchange](https://i.stack.imgur.com/GNpOf.jpg)
wiring - How to add Thermostat C Wire to Furnace TH/TR and Transformer - Home Improvement Stack Exchange
![Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to](https://i.redd.it/j9mnonzn7nu91.jpg)