Miller® Smith® Model 30 Argon/Nitrogen Regulator Kit CGA-580. Series 30 Single-Stage regulators are extremely durable and contain our exclusive Sure Seat™ filtered seat technology for extended seat and regulator life. Filtered seats prevent contamination from entering the seating area, reducing repair costs and downtime. These highly accurate regulators are manufactured with a rugged forged body, corrosion-resistant bright nickel-plated bonnet and a highly durable neoprene composite diaphragm.