SRAM's TT Chainrings are stamped from 7075 aluminum for low weight and excellent strength. The teeth are ramped and pinned for precision shifting with a SRAM Yaw front derailleur. This chainring is only compatible with SRAM RED Exogram cranks. RED Exogram crank have a hidden 5th bolt behind the crank arm. It is not compatible with Force, Rival or non-Exogram RED cranks.