Amazon.com: 688-2RS Ball Bearing 8x16x5mm,ABEC-3 8x16x5 Blue Rubber Sealed Ball Bearings (Pick of 10pcs) : Toys & Games
R3-2RS Bearing Miniature Ball Bearing 3/16x1/2x0.196 Inches Both Sides with Rubber Sealed and pre-Lubricated with Grease: Amazon.com: Industrial & Scientific
R166 ZZ Bearing, ID 3/16 inch x OD 3/8 inch x 1/8 inch Miniature Ball Bearing, Metal Shielded and Pre-Lubricated with Grease, 3/16 inch Precision Roller Bearing (10 Pack): Amazon.com: Industrial & Scientific