Onlyfire Whole House Propane Tank Brass Air Mixer,2 PCS Built Heavier, Bigger, and Safer than others on the Market.Should only be used with low pressure systems (11" WC). 100% Solid Brass Construction makes it CORROSION RESISTANT . The Propane-Air Mixer is designed to allow air to enter the gas stream. The added air will reduce the amount of soot produced by propane gas. We recommend this product for liquid propane (LP) gas fireplaces or fire pits, when using the Fire Pit Ring Burner. Please be kindly pay attention about the air mixer: 1.This appliance can just use to LPG only, NG is not applicable; 2.To be safer, it's better use a banner to connect the coupling and 1/2 NPSM part tight, in case of gas leak.