The Helios FSD 200 is a durable flexible duct constructed from aluminium casing. It features a perforated inner surface that securely holds a mineral wool lining approximately 58.5 mm thick, offering effective sound insulation. Spigots on both ends allow easy connection to other ducts or attachment to fans via a pipe clamp connector (BM). The pressure drop of this duct is roughly four times higher than that of equivalent rigid ducting.