The design of the half-star PG 1070 cassette helps maintain a high level of performance gear change while creating a combination cassette / chain quieter. Design of cassette performance crossing high speeds with a combination chain / cassette quieter Design in half star: lightweight, durable, efficient Weight checked Alltricks : 243 g (12-27) Speeds : 10 Recommended system : PC-1091R, PC-1091, PC-1071, PC-1051, PC-1031 Sprockets on the star : 3 Material of the wheel lock : 7000 forged alloy Material of the pinion : Heat treated steel Group recommended : SRAM Force, SRAM RivalSprockets : 11-28 : 11, 12, 13, 14, 15, 17, 19, 22, 25, 28. 12-27 : 12, 13, 14, 15, 16, 17, 19, 21, 24, 27. 12-28 : 12, 13, 14, 15, 16, 17, 19, 22, 25, 28.