uxcell 688-2RS Deep Groove Ball Bearings 8mm Inner Dia 16mm OD 5mm Bore Double Sealed Chrome Steel Z2 20pcs: Amazon.com: Industrial & Scientific
10pcs 688-2RS Ball Bearings Set, Rubber Sealed Deep-Groove Ball Bearings Metal Bearing for Small Hobby 5mm Shaft or Rod Projects, 8x16x5mm: Amazon.com: Industrial & Scientific