Enduro39s 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 and 52100 high carbon chromium alloy mirror polished races this combination allows enduro39s abec 5 bearings to use tolerances twice as tight as abec 3 and operate without any noise the graphitenylon ball retainers allow virtually frictionless movement and provide constant lubrication to maximise the life of the bearing