The bracket is reversible and fits both 20 and 25 cm deep shelves, depending on which side of the bracket you mount the shelf on. Mount the short side on a 20 cm deep shelf and the long side on a 25 cm deep shelf. Screws are not included. Different wall materials require different types of fixing devices. Use fixing devices suitable for the walls in your home. If you are uncertain about what type of fixing devices to use, please contact your local hardware store.