The term Gondola shelving refers to a fixture to display goods that has a flat base and then an adjustable vertical component. A gondola shelving unit may be wall or aisle mounted and is often used to create maximum selling space in stores. The back panel of the shelf usually describes how it will attach to the other shelves. For example, if you have to install the shelf at an angle, your back panel would need holes for screws to attach such as with wood or metal shelves so you can screw them into other shelves on the wall. On most modern ones though they are just screwed onto brackets which are attached directly onto your existing wall studs so they can float freely between two supports.