These gas logs are set up for propane gas. They are 21" wide by 12" tall by 12" deep. No vent needed. Thermostate control. Set it and forget it. These put out enough heat for a very large room or a small house. We were using these in a small house and it was the only heat we needed. We moved and don't need them anymore. I don't have a propane bottle to show how they work but they were working great when I removed them. Call or email if you are interested.