The 684-ZZ is a Premium Miniature Single Row Deep Groove Ball Bearing engineered for reliable, high-speed rotation in space-constrained mechanical environments. Characterized by its double-shielded design (ZZ), this bearing is expertly sealed with twin metallic shields that lock in essential lubrication while repelling airborne dust and fine particulates. Featuring a versatile 4mm bore and a compact 9mm outer profile, the 684-ZZ is the definitive solution for micro-motors, precision instruments, and automated assemblies demanding superior operational stability without adding excess bulk.