The main structure of the LA2 spray gun is the way in which the combustion chamber is connected to the primary combustion nozzle, with a portion of the air used for combustion support and a portion used for cooling the gun body and directly discharging it out of the gun.

The main structure of the LA3 spray gun is the connection between the combustion chamber and the two-stage combustion nozzle. Part of the air is used to support combustion, while the other part is used to cool the front end barrel. The cooled air is then folded back into the barrel and mixed with secondary propane and air for combustion, generating more heat energy. After combustion, the flame gas instantly expands several times, and the driving force of the powder particles inside the gun body is stronger, resulting in higher particle flight speed, lower porosity, and higher coating hardness.