6-piece painted concrete logs. Cast dual fuel log set can convert any wood burning masonry fireplace into a clean burning, low maintenance LP (propane) or natural gas vent-free fireplace. Vent-free design keeps 100% of heat in the home. Deep textured, charred look split oak sets are hand painted to provide maximum realism. Large U-shaped burner provides dancing yellow flames intermingled throughout the logs. Includes built-in thermostat to maintain desired room temperature. Log mounting design provides exact placement of each main log, while a pin system provides sure placement of each auxiliary log. Check state and local codes for permitted uses. Do not attempt to operate heater above elevations of 4500'. Lava rock included.