List for $228.49 and still being sold:

"Designed for use with all types of heating equipment with inside flue temperatures exceeding 350F, skin temperatures of 250F
Installs easily using basic household tools.
Thermostatically controlled; factory preset to provide troublefree operation.
Plugs into an standard 110v home outlet.
Unit size 14 3/4" H x 10 3/4" Wx 14" D
Crimp is on the bottom."

Yes, they cause a lot of condensation . Available in 6" & 8" diameters.
Bob

__________________
Keep the fire in the fireplace.