There are two installation methods compatible you to choose, you can install this door stopper with screws or not, the compatiblemer method can provide you with more stable installation and the latter will not damage the wall. Embedded design allows this door stopper to have better ability of anti-collision, and choice material enables it to have good rust and corrosion resistance, which can provide you with excellent percompatiblemance. Stainless steel and rubber are the materials used to make this door stopper, which is not easy to rust. 75mm, 95mm, 120mm, 150mm are the different specifications that you can choose from, each of them has different sizes. You can install this door stopper on the doors of bedroom, bathroom, office and so on. Item Name: Punch-free Door Stopper Material: Stainless Steel,Rubber Color: Silver Color Installation Methods: Punching/Punch-free Length/Specifications: 75mm, 95mm, 120mm, 150mm Features: Anti-collision Rubber, Not Easy to Rust, Anti-corrosion Size Details: 75mm: 7.5cm x 4cm x 4cm/2.95" x 1.57" x 1.57" (Approx.) 95mm: 9.5cm x 4cm x 4cm/3.74" x 1.57" x 1.57" (Approx.) 120mm: 12cm x 4cm x 4cm/4.72" x 1.57" x 1.57" (Approx.) 150mm: 15cm x 4cm x 4cm/5.91" x 1.57" x 1.57" (Approx.) Base Diameter: 4cm/1.57" (Approx.) Head Diameter: 1.6cm/0.63" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Door Stopper