12 size precision steel balls assortment kit contains: 90pcs1mm 80pcs2mm 80pcs2.5mm 50pcs3mm 50pcs3.5mm 50pcs4mm 50pcs4.5mm 50pcs5mm 30pcs5.5mm 30pcs6mm 20pcs7mm 20pcs8mm. Made of 304 Stainless Steel. Uniform size, high wear resistance, high precision, smooth surface, no burr, exquisite appearance. Widely used in auto parts, motorcycles, bicycles bearings, casters, drawer slides etc. It can also be used as a mixing balls. Used to stir paint, nail polish, etc The surface is coated with a small amount of grease to reduce friction when the bearing rotates and prevent corrosion and rust.Will reduce the damage to the machine and extend the service life. Storage box packaging. steel balls are sorted by size and stored in compartments of the box. Easy to identify and store. Note:due to different production batches, the plastic box style is random Colour:Silver Material:Stainless steel Size:10.01x3.99x1.30 cm Package Contents: 600 x 12 Size Stainless Steel Precision Steel Balls Only the above package content, other products are not included. Note: Light reflection 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.