Flush trim router bits are of the most utilized router bits in the workshop and are extremely easy to use. Veneers and finishes are trimmed down to match the size and contour of the material it is applied to and cabinet face frames are trimmed to be flush with cabinet end panels and any other flush trimming application. As a general rule, larger diameter flush trim bits produce the smoothest finish but reduce the ability to fit into small spaces. It is best to have a variety of sizes to best suit your application.