Nothing really fancy but purely functional, simple and work great. Ripping long boards, cutting larger sheets, etc. these make for that extra set of hands we all need at one time or another. The 'hook' on the top front end simply 'snug' fits into the slot between the rip fence tube and the angle that mounts this tube to the saw. Allows the extensions to be put anywhere along the infeed side. Fold up for easy storage when not in use. Make yourself a set !!