Does your bookcase have large compartments that are of no use to you? If the answer is yes, you should install this extra shelf in your bookcase so that you have more space to store your things. The best part about this extra shelf is that it can be easily mounted on PL154, PL155, and PL156, and it will help you keep all your office equipment safe and organized. There are seven finishes to choose from so that you can match it to your bookcase. By installing this extra shelf on your bookcase, you will be able to more easily store your files, laptop, or other office equipment.