SCREW ON DESIGN: The internal thread design of the lug nut covers is tighter than the embedded nut cover and is not easy to fall off. It also protects your bolt head from dust and , and protects the internal structure. These designs are and stay fixed to your hub even on bumpy roads ATTRACTIVE & RUST-: lug nut covers are made of premium ABS, which has a mirror-like finish after being chromed and polished. In addition, they are heat , waterproof and prevent rust, which makes your vehicle more dazzling and shiny EASY INSTALLATION: The threads of our screw-on lug nut caps are very precise and standard, which can perfectly fit the bolts of your semi-truck trailer wheel hub. Just tighten it, and it comes with an installation tool, which is very easy to install. The thread design makes the installation very secure and not fall off while driving Colour:Photo Color Material:ABS Package Contents: 12Pcs x Lug Nut Covers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.