The anchor is made from marine grade concrete and can contain air or water. For transport it contains air and gets towed to its destination. There it's ffilled with seawater and sunk to its ffinal location on the seabed. For maintenance it's ffilled with pressed air until it floats up to the surface, allowing underwater parts and connections to be inspected and maintained. The anchor proactively enhances marine biodiversity as its structure is suitable for early food chain organisms to attach and develop.