The shelves are secured to the wall with a bottom support rail which is attached to the shelf as one piece. The metal knurled support arms are screwed to the wall for support with four screws which are shown on the square polished nickel base plate. The top of the support arm screws to the shelf with a single screw. Crafted of Lucite® acrylic and brass Hangs horizontally Approx. 36"W x 12"D Shelf, approx. 0.75" thick Includes hanging hardware Hanging method: screw Wipe clean Imported Weight, 18.0 lbs Boxed weight, approximately 21.0 lbs Proposition 65 warning for California residents Shipping Direct from Vendor, usually ships within 15 business days.