The ^Opti-Myst® fireplace insert from Dimplex uses a revolutionary ultrasonic technology that uses steam to create impressive flame and smoke effects. It’s not gas. It’s water. As steam is released from the ember bed, light reflects off the water molecules, creating a visually convincing effect of flame and smoke. Each fireplace features an easy-to-fill water tank that provides 12 to 14 hours of continuous operation. The Opti-Myst^® fireplace insert is completely safe – cool flames and zero emissions. It’s the perfect way to enjoy the ambiance wherever you are.