Using the same quality standards as our regular steel bearings, these Ultra-Glide™ bearing assemblies feature satin-smooth Delrin® sleeves. Delrin® is an industrial synthetic plastic material similar to nylon, and will leave no marks on the material being cut. Applications include solid-surface materials such as Gibraltar®, Corian®, Surell® & Fountainhead®. etc.; Plexiglas® & other clear acrylics; and plastic laminates. Not recommended for regular wood applications due to a higher wear factor. Include Teflon® dust shields. These bearings provide a better seal to increase bearing life while routing materials that generate very fine dust particles (such as solid surface). Includes new Teflon® dust shields.