Features: brand new and high quality Stainless steel material: anti-rust and anti-corrosion. Rolling elements: high-precision steel balls, which greatly transfer the load between the inner ring and the outer ring of the bearing. Cage: Optimize load and reduce frictional heat. Integral-seal: retain bearing grease to reduce foreign matter from entering the inside of the bearing. Bearing ring: including the inner ring and outer ring of the bearing, the use of low-oxide high-purity bearing steel greatly improves the hardness of the bearing. Package Includes: 10x Bearings Specifications: Material: Stainless Steel Size 1: Approx. 1.5x4x1.2mm/0.06x0.16x0.05inch Size 2: Approx. 1.5x4x2mm/0.06x0.16x0.08inch Size 3: Approx. 2x5x1.5mm/0.08x0.20x0.06inch Size 4: Approx. 2x5x2.5mm/0.08x0.20x0.10inch Size 5: Approx. 2x6x3mm/0.08x0.24x0.12inch Size 6: Approx. 3x7x3mm/0.12x0.28x0.12inch Size 7: Approx. 4x7x2mm/0.16x0.28x0.08inch Size 8: Approx. 4x8x3mm/0.16x0.31x0.12inch Size 9: Approx. 4x9x4mm/0.16x0.35x0.16inch Size 10: Approx. 4x11x4mm/0.16x0.43x0.16inch Size 11: Approx. 5x11x5mm/0.20x0.43x0.20inch Size 12: Approx. 6x13x5mm/0.24x0.51x0.20inch Size 13: Approx. 7x11x3mm/0.28x0.43x0.12inch Size 14: Approx. 7x17x5mm/0.28x0.67x0.20inch Size 15: Approx. 7x22x7mm/0.28x0.87x0.28inch Size 16: Approx. 8x22x7mm/0.31x0.87x0.28inch Size 17: Approx. 10x22x6mm/0.39x0.87x0.24inch Size 18: Approx. 12x28x8mm/0.47x1.10x0.31inch (Size=Inner Hole x Outer Diameter x Height) note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.