The Cozy is made from 18 gauge galvanized steel. It is very strong and won't get hot to the touch. It's totally safe to place objects on top including plants.
The Cozy system itself is composed of an insulating enclosure, which traps convection, and a thermostatically controlled fan, which provides forced convection when activated. The system incorporates a wireless radio, which syncs room and radiator temperatures to a cloud database.