These flush trim plunge router bits are versatile, useful for template/pattern routing of parts,joints, and internal cuts, and can be used in hand-held and table-mounted routers. They are essentially plunge-cutting straight with shank-mounted ball-bearing pilots. The template is attached to the workpiece, and the pilot bearing rides along its edge as the cutting edges rout the workpiece, forming an exact duplicate of the template. With a hand-held router, the pattern is on top of the work; with a table-mounted router, the pattern is underneath the work.