In small to medium pressure programs, the most common link type is usually a flared fitting. One flare SAE 37° is the standard for most hydraulic devices. SAE expectations for the most tube wall thickness should be followed ahead of flaring the tube to match the fitting relationship. This SAE http://valvesandfittings27161.mpeblog.com/12218318/5-simple-statements-about-sae-flareless-fitting-explained