Astria's unique, clean burning design provides 99% heating efficiency, allowing you to operate the logs vent-free with the fireplace damper closed. With no venting required, there is no heat loss up the chimney. Plus heating with Astria gas logs means you’ll never again be left in the cold with wet logs or without heat during a power outage. In addition to vent-free safety controls and industry leading clean flame combustion technology, the log set is unitized in a pre-assembled arrangement. This feature assures maximum performance and eliminates the possibility of log misplacement or movement, which could affect indoor air quality. The control and gas train are 100% factory assembled and tested. The unitized design also makes installation a breeze! Just complete the gas connection using the shut-off valve and stainless flex connector provided. Astria's Dual Burner Vent-Free Gas Log Heaters offer the choice of four types of remote control accessories as well as the ability to operate the log heater with manual control.