The inner VBC (Variable Bolt Circle) chainring is made to be paired with an outer VBC chainring with elongated five window design that replaces the traditional chain ring bolt circle. The windows are allow the inner ring to self-center without being confined to a specific bolt circle.
They are CNC machined out of 7075 aluminum, hard anodized black. Tooth counts: 38, 36, 34, 32, 30, 28, 26 and 24
VBC chainring bolts sold separately (see related items to the right of the screen)
Made in the U.S.A.