Universal Pneumatic Fitting for Multiple Sizes Compatible with 1/8, 1/4, 3/8, 1/2 female threads, this quick connector fits tubing with outer diameters of 4mm, 6mm, 8mm, 10mm, 12mm, ensuring versatile use across various pneumatic systems. Copper Construction for Durability Made from premium copper material, this fitting offers excellent resistance, high strength, and reliable performance under pressure in demanding pneumatic applications.