Everything you need to install peel and stick wallpaper is here in this kit. Use the smoother to remove air bubbles from under the wallpaper. Use the knife to trim the removable wallpaper to your desired needs. While a credit card or other hard edged tool will work, this kit is designed for peel and stick wallpaper installation and has been used in hundreds of installations. This is the kit that we use to install wallpaper in our own spaces.