404 - 404 Gas Diffuser for Tregaskiss 300A/400A MIG Guns

Keep Your Arc Smooth and Stable

When your MIG gun starts sputtering or your gas coverage gets spotty, the problem is often hiding inside the nozzle. The 404 Gas Diffuser (Tregaskiss Style) is the workhorse part you need to get your 300A or 400A torch back in action. Designed for the "Old Style" Tregaskiss guns, this diffuser is built to handle the heat and keep you welding.

A good diffuser does two main jobs: it transfers the welding current to the contact tip and it smooths out the flow of shielding gas around the weld pool. If your old diffuser is clogged with spatter or the threads are stripped, you're going to fight your equipment instead of focusing on the bead. This replacement part is machined from solid brass to stand up to the daily grind of the shop floor.

Installation is straightforward—simply unscrew the old unit from the gooseneck and thread this one on. It seats securely, providing a solid base for your contact tip. Because it's a standard duty part, it's perfect for general fabrication, structural steel, and repair work where 300-400 amps is the sweet spot. Don't let a worn-out front-end part ruin your weld quality; swap in a fresh 404 diffuser and notice the difference in arc stability immediately.

This part is compatible with the consumables you likely already have in your bin, specifically those designed for the classic Tregaskiss setup. It's a smart, affordable way to extend the life of your trusty MIG gun.