RaceFace NEXT SL G4 Crankset 175mm No Chainring Direct Mount 30mm/ 100mm Carbon 30mm spline interface CNC'd from aluminum super alloy Fully hollow carbon crank arms and super alloy pedal insert for maximum weight reduction CINCH removable spiders and direct mount rings utilize a 20-tooth ISIS cup BB tool for removal and installation 2X Cinch spider chainline: 77mm Boost 2X Cinch spider chainline: 80mm