The Duluth Forge Berkshire Stacked Oak Vent Free Log Set features Patented Dual Fuel Technology which allows you to purchase this log set to use with either LP Gas or Natural Gas. This unique log set offers a natural look and feel of a real wood-burning fireplace. The log set was developed from real wood to reflect a bark stack with focus on blending bark and split features along with charring to create an exquisite look to your fireplace and magnify the beauty of your home. The Thermostat Control feature can easily regulate the 33,000 BTU to create the perfect heat setting for your home. Product Features 33,000 BTU Heats up to 1,300 sq. ft. Patented DUAL FUEL TECHNOLOGY 1 Unit operates off Natural Gas or Liquid Propane Thermostat Control - The control automatically cycles the burner on and off to maintain a desired room temperature 8 hand painted realistic detailed logs using superior refractory ceramics to ensure a long life-span Solid, well-built black powder coated chassis Ember Burner chassis design provides one row of flames and a glowing ember bed to create a realistic fire High End Ember Burner chassis has a large glowing ember bed appearance and gives a more lifelike look Economical: 99.9% efficient. No outside duct or chimney needed! Safety Assurance: SAFETY PILOT O.D.S. (Oxygen Depletion Sensor) included with automatic shut-off Battery Assisted Piezo ignition (Requires 1 AAA Battery - Included) Must be installed in a masonry or agency approved firebox Minimum Firebox Size Required: 20” H x 28” W in front (23” W at rear) x 15” D Safety Assured ANSI Certified System PFS Approved Designed for Indoor Use Only 1 bag of glowing ember material included Ships in 2 Boxes