Left side 142x12/148x12mm insert for 160mm brake rotors and SRAM UDH Dropout inserts. This insert fixes the position of the left hand slider so that it matches up with the right hand SRAM UDH dropout insert. This is not required to run a SRAM UDH drivetrain however it makes setup much easier and no forward tension screws are needed with the dropouts.
For 160mm rotors, or larger with appropriate brake adapter