These shelves slope downward which make them perfect for displaying books, greeting cards and compact discs. As noted they are made with both ends open (perfect if you want to add another J Rack next to each other for a longer display) or both ends closed. Each of these J Racks have a 2 1/2" front lip and are made from 1/8" acrylic. Because of their unique shape, shipping costs for these items are fixed. However some items may be re-quoted if the calculated freight cost is too high or too low. We will review your order before shipping and contact you if adjustments are necessary.