ALL SHELVES ARE 3/8 OF AN INCH THICK, CLEAR, TEMPERED GLASS. UNLESS NOTED DIFFERENTLY. SQUARE SQUARE 12 X 12 S12$44.50 SQUARE 16 X 16 S16$54.20 SQUARE 20 X 20 S20$69.00 ADHESIVE CAULKDON'T FORGET TO GET THE ADHESIVE CAULK! IT IS THE ONLY SUPPLY NEEDED FOR THE INSTALLATION OF THE GLASS CORNER SHELVES!