What are the characteristics of a good tube fitting?

A good tube fitting should ensure a leak-free seal under various pressures and temperatures, providing reliability in fluid transfer. It should be durable, made from high-quality materials that resist corrosion and wear. Additionally, ease of installation and maintenance, along with compatibility with different tube sizes and types, are essential characteristics that enhance its functionality. Finally, a good fitting should allow for smooth flow to minimize pressure drops in the system.