Qmark Wall Heater Series CWH3000, LFK, CWH1000 and GFR are discontinued and replaced with the “F” suffix models.
The replacement models, which were released in September 2014, have the “F” suffix. The new products have improved aesthetics and airflow.
The new Qmark wall heaters:
https://morelectricheating.com/products/WALL%20HEATERS/LFK.aspx
https://morelectricheating.com/products/WALL%20HEATERS/GFR%20SERIES%20WALL%20HEATER.aspx
https://morelectricheating.com/products/WALL%20HEATERS/CWH-1000%20SERIES%20WALL%20HEATER.aspx
https://morelectricheating.com/products/WALL%20HEATERS/CWH-3000%20SERIES%20WALL%20HEATER.aspx