YourPoolParts offers a full line of permanent ceramic depth and safety tiles. Our tiles are printed with ceramic glaze inks, then kiln fired to ensure the finest most durable depth and safety marker line available. The ceramic tiles are available in smooth surface for the waterline, and skid resistant surface for deck or gutter applications. The skid resistant tile is surfaced in the factory - not sanded or coated - for a more reliable slip resistant surface. This particular line offers 6" x 6" smooth and skid resistant tiles with four-inch numbers, and two-inch or four-inch letters. They are centered vertically and horizontally.