Yup, NAPA sells it. Big two piece aluminum housing that separates with a large T handle through bolt. Uses replaceable cartridges. IIRC was under $50. I just bolted it to the plasma cart and ran the plasma airline right to it. Just hook shop air to the filter and it’s good to go. I’ll have to look at one on my plasmas and see if I can pull a part number from it for you. I can’t find it on their webstore.
FYI…shop air can be used for most metals, including aluminum up to 11 gauge. Stainless you need to use pure argon or helium, or a proper mix of either.