The DY-2 1/4 x 40 TPI 90° Elbow Fitting for Live Steam Models is a must-have for any modeler. It's a high-quality, durable elbow fitting designed to fit steam models with a 3mm bore. The rotating elbow allows for easy fitting of tubing and connections, making it perfect for any steam-powered project. With its precision TPI (threads per inch) measurement, you can be sure it will securely attach to your model's fittings. The 2-pack ensures you'll have enough elbow fittings to complete your project, no matter how complex. Choose DY-2 for superior quality and performance in your live steam model projects.