1. It is made of brass, being relatively sturdy and durable with an exquisite appearance. 2. It is relatively easy to use and convenient to replace. 3. It can lower the center of gravity and improve climbing performance. 4. The weight of each front inner axle housing is approximately 9.5 grams. 5. The weight of each caster base is approximately 5.5 grams. 6. The weight of each outer axle housing is approximately 5.5 grams. 7. Applicable vehicle models are FCX24 1/24 scale remote - controlled climbing cars. 8. Colors: 1. Black. 9. Material: Brass. 10. Package contents: - 2 brass front inner axle housings for remote - controlled cars. - 2 brass outer axle housings for remote - controlled cars. - 2 brass C - type steering knuckles for remote - controlled cars. - 1 set of installation accessories for remote - controlled cars. 11. Generally, only the above package contents are included, and other items are usually not included. 12. Note: Light reflection and different displays may cause slight differences between the item color and the actual object. The measurement tolerance is about ±1 - 3 cm.