1. Product Overview 61868MA belongs to 618 ultra-thin wall single row deep groove ball bearing series, open type without seal or shield, overall dimension 340mm inner bore × 420mm outer diameter × 38mm width.Suffix explanation: MA: Solid machined brass cage, outer ring guided, high rigidity, high temperature resistance, stable performance under high speed and heavy load, good anti-deformation capacity under vibration. Ultra-slim cross-section design greatly saves radial