BiOrb Marble pebbles are solid polished stones which won't cloud the water. Once in water, the colour of the pebbles deepens and shines. This set comes with white pebbles of varying natural sizes. When decorating your underwater world, use pebbles to complement your plants and sculpture and decorate the bottom of your BiOrb. Maximum pebble size is 7 x 4.5 x 4 cm. Oase biOrb Marble Pebbles are a large and realistic looking marble pebble stones. The pebbles can be added to the base of your fish tank to add a decorative touch to the aquarium as well as covering any ceramic media below it. The Marble texture of the pebbles is smooth looking and safe for the fish. The biOrb Marble Pebbles add colour and interest in an aquarium and when combined with other plants, creates a vibrant display for you to enjoy. The stones can be easily placed and moved in the tank. It is recommended to wash the stones before placing into the aquarium. Specifications Approximately 8-10 pebbles per pack.