ASD Fuel or Transmission Line Unions for 5/16" Tube (1/2" - 20 Thread, Inverted Flare) (Pack of 5). Constructed from safe and professional quality brass, these unions are lead-free and high-pressure resistant, making them durable and reliable for use in automotive brake line systems. Designed to fit the most common 5/16" SAE inverted flare / double flare size, these unions are ideal for a wide range of applications. They are compatible with 5/16" steel, copper, nickel poly armour, and cupronickel tubing, which makes them versatile and easy to use with your preferred brake line of choice. The pack of five unions is designed for convenient use, allowing you to stock up on spares and minimize downtime in case of replacement. These unions feature a 1/2" - 20 thread, which makes them easy to install and ensures a secure fit. Auto Supplies Direct is a trusted brand among brake line mechanics, ensuring that you can trust the quality of these unions. They are not only ideal for use in automotive brake line systems but also versatile enough to use in other mechanical projects. In summary, the ASD Fuel or Transmission Line Unions for 5/16" Tube (1/2" - 20 Thread, Inverted Flare) (Pack of 5) offer high-quality construction, multiple compatibility, a standardized size, a convenient pack size, easy installation, high-pressure resistance, and a trusted brand name, making them the ideal choice for any brake line mechanic looking for a reliable and versatile union.