Make of high quality brass,with fine workmanship and perfect style, more stronger and durable, improve the apprance. Add more weight so as to lower the center of gravity and enhance stability of your rig. Fine workmanship and perfect style. Lower the center of gravity of car, increase balance. Great function, increase balance,lowering center of gravity and increase stability. Easy to operate,not complicated installation steps,convenient install,shock-proof and high crush-resistant. Practical design,lightweidht upgrade,exquisite workmanship improve the performance of your crawler car. Material:Brass Size:Approx.3.8x1.3cm/1.5x0.51inches Outer Diameter: 38mm Compatible with TRX4 1/10 RC Crawler Car 2x Wheel Rim Internal Counterweight 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.