Compatible with ALL BiOrb Classic, Tube, Flow, Halo & Life Aquariums. The three Urchins are approx. 2." x 1.5", 2.5" x 1.5" & 1.5" x 2". Also a great addition to non-BiOrb Aquariums. Transform your BiOrb aquarium into a mesmerizing aquatic paradise with the BiOrb White Sea Urchins Set. This exquisite set of sea urchin decorations adds an enchanting touch to your underwater landscape, captivating both you and your aquatic inhabitants. Crafted with meticulous attention to detail, each sea urchin ornament is handcrafted using premium materials, ensuring not only their stunning beauty but also long-lasting durability. Installation is a breeze with the biOrb White Sea Urchins Set, as it seamlessly integrates into your biOrb aquarium. You can easily attach these elegant ornaments to the ceramic media or directly to the BiOrb patented filtration system, creating an awe-inspiring underwater display without any hassle.