10-Pack Router Cutter Bearings 1/4" x 1/2"Ball Bearings R188 ZZ 1 4" x 1 2" x 3 16" Inch Lot of 10 Bearings High Quality 10 Router Cutter Ball Bearings, measures an inner diameter of 1 4", outer diameter is 1 2" and the width is 3 16", each Comes with double metal shields (ZZ) to keep out dust and dirt, additionally, these bearings come pre lubricated with grease for smooth operation. Double Shielded Ball Bearings Deep Groove Ball Bearings Shield Double Metal Shields for dust protection (ZZ)