set2: 10 x Miniature Ball Bearings + 10 x Deep Groove Ball BearingsClosed with metal shields to protect the bearing from dust or any possible contamination. Commonly used for Electric Motors, Wheel Bearings, Agricultural, Conveying and much more.684ZZ Shielded Ball Bearing, Bearing IS made of Bearing Steel, each bearing has 2 Metal Shields to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease.684zz bearing is a kind of multi-purpose miniature bearing.It widely used in precision instruments, Minimotor, remote control model, etc industries.Product Name : Deep Groove Ball Bearing;Model No. : 6800Z/684ZZInner Diameter : 10mm / 0.4 inch;Outer Diameter : 19mm / 0.75 inchHeight : 5mm / 0.2 inch;Color : Silver ToneMaterial : Metal/Bearing SteelSize:4 x 9 x 4mmPackage Contents:10 x Miniature Ball Bearings10 x Deep Groove Ball BearingsOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.