Forged 6000 series, cnc machined alloy body. 225 grams. 7000 series alloy axle with alloy end caps. The hub uses two 6901 series dual contact seal bearings for a super smooth performance. The cassette body also uses two 6901 dual seal bearings and has a forged and machined alloy body. Fits Shimano or Sram 8,9,10,11 Speed.