SeaStar - Union Coupling Tee Fitting - 3/8" - HF5527 This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet your needs and deliver great quality at an affordable cost. All SeaStar Manual Hydraulic steering systems utilize the same style of fittings for all applications. Features: These are 3/8" compression fittings that utilize a 9/16" 24 extra fine thread For Use with 3/8" nylon and or 3/8" copper tubing Carefully crafted to suit your specific boating needs Engineered to high standards High-grade design delivers an extended lifespan.