The 626zz bearing is a miniature, double-shielded deep groove ball bearing. "ZZ" indicates that it is fitted with a metal shield on both sides to help keep dust out and retain lubricant, allowing for high-speed operation.
The 608ZZ is a versatile and widely used deep groove ball bearing with specific dimensions, double metal shields, and a wide range of applications, especially for moderate loads at high rotational speeds. The 608ZZ designation indicates its key features: 608 for its size, and ZZ for its shielding.