Creating a stable router platform: The obvious issue to trimming the protruding head of a dowel or lipping. Is that the base of the router hits the dowel even before the router cutter gets to it. The Edge Trim Kit Riser clips onto the underside of the CRB7 and acts as a 7mm (1/4") platform. The platform has greater router to work surface contact area much more than the base of a regular router which ensures stability throughout the routing pass. Maintaining a consistent cutter height: Critically The CRB7 Trim Kit Riser maintains a consistent distance between the bottom of the cutter and the work surface. The requirement of the woodworker is to do as little work to completely flush the dowel head as possible; So the router cutter needs to be all but touching the surrounding work surface. At such close proximity even a small variation in cutter height could see the work surface inadvertently routed and as dowels are fitted after the wood is machined. Damage as this point could be almost impossible to rectify. The CRB7 Trim Kit allows a single routing pass to flush the dowel head or edge lipping requiring just light abrasive to finish. Increasing the speed of the routing pass with the Tracer Racer: The Edge Trim Kit includes a bearing race and mounting post. when fitted this removes the need for the woodworker to visually guide the router along the path of the lipping. The tracer bearing runs along the edge of the board keeping the cutter directly over the lipping ensuring the routing pass flushes the lipping in one go. It's well built - The Riser is machined in solid 7mm Acrylic sheet with steel passivate locating dowels and is manufactured in the UK.