These are our eccentric bottom bracket cups designed for getting just the right chain tension on any bottom bracket with a 46mm ID (e.g. PF30, BBRight, Specialized OSBB, etc). They have 5mm of eccentricity for minimal offset of pedaling stroke. Hard anodized for additional durability. Fits 68mm and 72mm width bottom bracket shells. Wider shells can be accommodated with longer M5 bolts.