Generally (but not always) pronouns stand for (pro + noun) or refer to a noun, an individual or individuals or thing or things (the pronoun's antecedent) whose identity is made clear earlier in the text. For instance, we are bewildered by writers who claim something like. They say that eating beef is bad for you.
A wire feeder may be used for machine or automatic welding and must be the constant speed type. The wire feeder must have a speed adjustment covering the range of from 10 in. per minute (254 mm per minute) to 125 in. per minute (3.18 m per minute) feed speed. PAW or plasma arc welding using an automated process.
It comes out of the same nozzle your welding wire is fed through so it literally creates a protective cloud around the arc as you're welding. A MIG welder is also a wire-feed type welder. The metal that it uses to create the weld material is held on a spool inside the welder. The type of material it uses depends on what type of metals you're joining, but it's always a metallic wire.