Dimplex DFI400LH Opti-Myst Cassette-Style Indoor Space Heater with Faux Logs, Black Opti-myst technology: Incredibly, life-like, patented 3-dimensional flame effect. Creates an illusion of fire and smoke. Pennies a day: Economical to operate: less than 1 cent per hour (flame only) or 7 cents per hour (cycling at 50%) Easy-fill water tank: Offers 14 to 17 hours of continuous operation before refilling is required. Green: The green alternative. No harmful particulates or emissions and 100% efficient On/off remote: Includes a convenient easy to use on/off remote for control at your fingertips.