RaceFace Respond Mountain Bike Crankset Arms are engineered using ultra-high strength 7050 aluminum alloy to maximize strength to weight ratio 6mm of chainline adjustment Includes Race Face HD Bottom Bracket Features the 'EXI' interface external bottom bracket system for easier crank installation and removal with standard tools and fully adjustable chainline Bearings are factory filled with Phil Wood waterproof grease  tested and proven to extend bearing life