The Fiji Cube Advanced Hang On Back (HOB) Refugium Box PRO SERIES Large is an external filtration system designed to enhance water quality and biological diversity in reef or freshwater aquariums. It features a robust hang-on design, offering a secure and space-efficient solution for setting up a dedicated refugium area outside the main tank. This model includes a unique baffle system that prevents substrate disturbance while ensuring quiet operation with sufficient flow, as well as an efficient Fiji Flow 300DC Nano DC pump with adjustable flow rate and feed mode function.