vidaXL Natural Red Volcanic Rocks - Beautiful Aquarium Landscape Decoration and Biological Filter, Suitable for Gardens - 3-5 cm Size, 25 kg Weight

【Wide Applications】: Volcanic rocks are also suitable for enhancing garden landscapes, planter beds and other landscaping applications 【Decorative Element】: The detailed and colourful natural shaping of these chunks provides a vibrant focal feature for your fish tank 【Natural Material】: Beautiful red volcanic rocks are 100% natural and safe, won't affect your aquarium's pH or chemistry 【Biological Filter】: The lava stone forms a natural biological filter, improving water quality, boosting oxygen levels, controlling nitrates 【Approximate Size and Weight】: These red volcanic rocks are around 3-5 cm, with a total weight of approximately 25 kg