Fast-Stat Common Maker Thermostat Wire Extender (Adds a Common C Connection) FSCM00 - The Home Depot
New - Fast-STAT Common Maker - Adds a Common"C" Wi-Fi Thermostats | eBay
Home - Fast-Stat
Fast-STAT Common Maker - Adds a Common"C" Popular Wi-Fi Thermostats - Amazon.com
New - Fast-STAT Common Maker - Adds a Common"C" Wi-Fi Thermostats | eBay
My existing thermostat is heat only (gas boiler) and has a 2-wire connection. To install a C-Wire ecobee support said to purchase a Fast-Stat Common Maker for each zone (makes sense), but
ECOBEE t-stat wiring — Heating Help: The Wall
FSCM00 - Fast-Stat FSCM00 - Common Maker Thermostat Wire Extender (Adds a Common C Connection)
Fast-Stat 1000 and Common Maker - Installation Guide – Simple
Fast-STAT Common Maker - Adds a Common"C" Popular Wi-Fi Thermostats : Amazon.ca: Automotive