Abstract: A tube coupling system for joining a plurality of metal tubes that are used in air flow systems which includes at least two tubular members each having at least one curled end. A clamping member is used to join the tubular members in an abutting interfacing engagement, the clamping member having a one-piece split coupler with two free ends which removably and circumferentially surround the joined tubular members along their curled ends. The coupler also has a spring locking member which is connected to the coupler free ends and moveable to connect and release the free ends and latch and unlatch the coupler from the members. A split pin can be used to secure the spring locking member. The clamping member coupler has a body portion and leg members affixed to and depending from the body portion so that the body portion and depending leg members are configured to envelope and grip substantially all of the curled ends of two connected tubular members.