Features: Color: Black/Golden. Gear Ratio:13-18T. Size: 18x11x7cm/7.09x4.33x2.76in. Composed of carbon fibers cage, 7075 aluminum-alloy pulley wheel and ceramics bearings. This system consists of Top 13T & Bottom 18T aluminum-alloy pulley wheels fit with low friction ceramics bearings and lightweight cage. Carbon fibers cage and 7075 aluminum-alloy pulley wheels provide high stability and strength while reducing weight. The entire system weighs about 87g. The frictional resistance of the non-resistance bearings is 60 percents lower than that of this ordinary pulley system, which can saving more than 2w of energy. Note: This model is only suitable for R7000/ R8000/ R8050/ R8070/ R9170/ R9150/ R9100. Specifications: Material: Carbon Fibre+7075 Aluminum-Alloy Color: for The Picture Shows Package Weight: approx.192g Style Options: 4 Style are Available for Shown in the Picture. Size: approx.18x11x7cm/7.09x4.33x2.76in Package Includes: 1Pc x Derailleur Pulley Wheel System note: Please allow 1-2cm error due to manual measurement. Please make sure you do not mind before you bid. Due to the differences between different monitors, the picture may not reflect the actual color of the item. Thanks!