The 634-ZZ is a Premium Miniature Deep Groove Ball Bearing engineered for applications that demand compactness and reliable performance. Featuring double metal shields (ZZ) on both sides, this precision metric bearing provides effective protection against dust and contaminants while ensuring low-friction operation. With a 4mm bore and a robust outer diameter, it is an ideal choice for small yet demanding applications such as precision instruments, high-performance micro-motors, and compact machinery where space is limited but durability is required.