Burton Disc Channel® Mounting Hardware is what you need to mount a Burton Re:Flex bindings or bindings that are disc mounted on a board featuring the M6 Channel.
The Burton 4x4 Channel® Disc is what you need to mount all Burton non-Re:Flex bindings on snowboards from different brands featuring the 4x4 system or on a Burton board featuring the Channel®.
The Burton 3D Hinge Disc is the part you need to mount all Burton Re:Flex bindings on Burton snowboards featuring the 3D mount system. Use M6 Mounting Hardware.