stainless steel & aluminum, and not easy to rust. The brake spring acts as a buffer to help the pipe from warping. Multi-color for your option: & gold/silver & gold/black & gold/red & blue/blue/gold & blue. Spring length: approx 9cm/3.5-inch, Whole length: approx 13cm/5-inch, Spring width: approx 1.6cm/0.63-inch. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!