Proprietary actuation ratio (only compatible with SRAM road shifters). Designed to optimize traditional and compact gearing shifts . Aluminum construction with shift-engineered steel cage. Braze-on model can be used with SRAM adapter clamps to fit 31.8/34.9mm frames if needed (use GS-8308/8309). 88g (braze-on), 102g (clamp). Features: Force model has titanium anchor bolts and limit screws,