Enduros ABEC 5 is the next performance step up from the popular ABEC 3 range. By using military level high precision HRC-64 hardended Grade 5 Chromium Steel Balls & 52100 High-Carbon Chromium-Alloy mirror polished races. This combination allows Enduros ABEC 5 bearings to use tolerances twice as tight as ABEC 3 & operate without any noise. The Graphite/ Nylon ball retainers allow virtually frictionless movement & provide constant lubrication to maximise the life of the bearing. Bearing Code: 7902 &40;71902&41; Dimensions: 15mm x 28mm x 7mm ABEC: 5 Grade: 5 Seals: LLB Grease: Kyodo Yushi PS-2 Application: Hubs Bottom Brackets Weight: 15.00g