A Simple but reliable door stopper to keep the door open or prevent damage to the wall when someone slam the door. This door stopper works on all surfaces. And the 2-pack bundle gives the extra power to stop a heavier door or keep one more door open. Please make sure both the surface and the door stopper are dry and clean before use it. Also, to generate the best friction to stop the door. We suggest you install the door stopper few inches ahead the ideal place you want the door to stop and this door stopper will generate enough friction when slides to the ideal place and finally stop at there.