Description:Race Face Race 4-Arm Chainring is CNC machined in the Race Face BC manufacturing facility. Outer, middle and aluminum inner rings manufactured from 7075-T6, one of the strongest alloys available today. Outer rings are made from 4mm thick material & middle rings from 5mm thick material for unsurpassed durability. Rings feature a patented S.H.I.F.T. technology, featuring hard wearing stainless steel S.H.I.F.T. chips for dual action up-shifts.