RaceFace Narrow Wide Chainrings feature tooth profiling for chain retention and a blend of weight and durability suitable for XC, DH, and everything in-between. - 7075-T6 aluminum, aerospace grade strength - Compatible with 9, 10, 11 and 12 speed - Stiff 4mm plate thickness and I-beam construction transfer loads without flexing - Reversible laser etched graphics - Non-threaded bolt holes