These wallpapers come with a water activated paste on the back of the wallpaper. They usually come in 20.5 inch widths and rolls that are 33 feet long. Depending on the pattern, you will usually get three full length panels out of a double roll. Also, they are generally sold as a double roll, but priced as a single roll.The installation requires you to cut the pieces in order matching each piece to the one before it and then wetting the back of the paper to activate the wallpaper paste. Once the wallpaper sheet is wet, let it sit for around five minutes before installing. Be careful , the saturated sheet may be very delicate.