10 PACK 4x8x3mm Metal Shielded Ball Bearings MR84ZZ - Apex RC Products #1910M 1 package includes ten (10) bearings. Direct oem replacement for traxxas, hpi, associated, tamiya, kyosho, and many other popular vehicles. Metal seals keep dirt out! Precision steel balls. Inner diameter: 4mm / outer diameter: 8mm / width: 3mm.