This Union binding disk is compatible with 4x 4, 4x 2 & Channel system. The universal disk provides increased response & locked in connection. Please note that the Union Universal Disk are only compatible with the following Union bindings; Forged Force, Atlas, Force, STR, Flite Pro, Trilogy, Juliet, Rosa and Cadet Pro. If the Union bindings you own are not listed, you most likely have a pair that is compatible with a Minidisk. Universal Disk (4X4 + Channel Compatibility): Align your disk with the boards inserts that you plan on using. Select your prefered binding angles. If you are using a traditional 4X4 mounting system be sure to use all four washers & screws. Begin by threading one screw with a washer. Make sure that the disk doesn’t move or you will have a hard time threading the remaining inserts. Next, thread the remaining screws & washers into place. If you’re using the Channel you will only need to use two washers & two screws to mount each binding. The Universal disk is not compatible with 3-hole insert pattern. Hardware should be hand tightened using a 3 Phillips Screwdriver.