Rugged, steel and aluminum alloy construction Metal backplate is 3D pressure-formed shape that optimizes stiffness, reduces weight, and leaves no rough edges to chip or peel off 260g (without bumpers) Designed in collaboration with NSMB Freeride Team and the Rocky Mountain Freeride Team Individually adjustable upper and lower guide arms Fits standard BB cups, new external BB systems and International Standard Chain Guide (ISCG) mounting systems. No adapters needed. Guides and arms can be adjusted without removing cranks or chain guide. Guide pulleys ride on Enduro cartridge bearings for maximum life. Precision tooth profiles designed to operate in near silence