Overall Dimension: 23.33”×15.64”×4” | Inside Dimension?: 14" x 14" x 3.88" | Inside Dimension?: 14" x 6" x 3.88" 100% WATERPROOF: We have the product done by injection molding which the part is to be one whole piece, no penetration of water, no leakage and 100% waterproof. 10 YEARS GURANTEE: Made by light weight and durable ABS material, will not rust and leak. DESIGN BY AMERICAN PROFESSION TEAM: Round corners, no sharp edge with safety; 4 side pre-sloped keep water off the shelf. EASY INSTALLATION: Surface with texture friendly with thinset application and easy for tile, stone or mosaic tile.