Size:1/2" Propane Air Mixer - 150k BTU Made of durable brass, our Propane Air Mixers are designed for most standard fire pits. Rated at 150,000 BTU's, our propane air mixers are crafted to work reliably for years to come. The majority of Propane (LP) fire pit burners require an air mixer. Why? Scientifically speaking, one cubic foot of Natural Gas requires ten cubic feet of oxygen for combustion. However, one cubic foot of Propane Gas requires 24 cubic feet of oxygen for combustion. That's 2.5 times more! Since Propane gas needs more oxygen than natural gas, air mixers must be used to obtain proper propane combustion. It can be an essential tool for your propane burner, with the additional benefit of reducing soot production created from using pure propane. We host online propane gas facts to help you get the most out of this mixer. We recommend working with a licensed professional who has experience in installing gas fire features. However, our propane air mixer includes easy to follow instructions if you choose to install yourself. Please remember to thoroughly test your burner before putting away your tools.