Light design, 12T only 12.8g, 14T only 14g. Size: 50 50mm (12T)/57 57mm(14T). Weight: About 12.8g (12T)/ 14g (14T). Deepen the tooth marks to reduce the chain loss, optimize the inclined tooth shape, and synchronize with the chain transmission direction, so that the chain entry and chain release are smooth.