684 is an open miniature ball bearing 684 bearing has an inner diameter of 4mm 684 small bearing outer diameter is 9mm and 684 bearing width is 2 5mm metric 4x9x2 5 mm 684 bearing is made of chrome steel grade 52100 52100 is a high carbon chromium containing low alloy steel heat treatment and hardening of 52100 alloy steels will get you 60 rockwell hardness and very common in bearings.
684 bearing ceramic.
684 pp tp c3 z s 5 af2 4x9x4 mm full ceramic bearing.
Ortech manufactures 684 hybrid ceramic bearings for extend service life reduce wear and minimize friction applications.
Glass ss ceramic.
Available in sealed shield open styles.
Abec 1 p0 abec 3 p6 abec 5 p5 4 internal clearance codes.
Nsk 684zz bearing 4 9 4 mm 684 zz deep groove ball bearing is the most representative of the rolling bearing widely used high speed or higher speed operation and very durable without regular maintenance.
Industrial packing individual.
684 plastic deep groove ball bearing.