YT Industries Jeffsy suspension bearing kit for carbon fiber frames manufactured from 2019 through 2021. For both Jeffsy 27 and Jeffsy 29 bike frames. Contains 8 pcs Enduro sealed cartridge bearings: 2 huge double-row deep-groove bearings, 2 pcs double-row MAX (full complement) bearings with black oxide anti-corrosion race treatment, and 4 pcs MAX single row bearings with black oxide.