SRAM XX1 BB30 1X11-Speed 175 156 Q-Factor with 32T Direct Mount Ring without BB New tooth profile alternates thickness by inner and outer links, providing maximum chain control Carbon arms with forged aluminum spider Weight: 650 grams with ring and BB(approx.) - BB not included Must be used in conjunction with SRAM's XX1 complete group (rear derailleur, cassette, shifter, chain, cranks/chain rings)