Our replacement ball bearings are designed to spin at high RPM and are double shielded to give you unparalleled performance. Use these premium ball bearings to replace worn out bearings on router bits, top bearing or other. Use the stop collars in combination with the bearings to make Top Bearing Kits for your 1/4" or 1/2" router bits. Common uses for our replacement router bit bearings is for slot cutter depth adjustment and Rabbeting router bit replacement.