Descriptions : 10pcs 623-ZZ 3x10x4mm Deep Groove Ball Bearings Miniature Bearings A popular size that could be used in many RC Cars and Trucks Specifications: Type: 623-ZZ Materal: Steel， Metal Size: 3x10x 4mm Inner Diameter: 3mm Outer Diameter: 10mm Thickness: 4mm Package included: 10X 623-ZZ Ball Bearings