This accessory allows a limited amount of ductwork to be attached to the air outlet on Quest Dual dehumidifiers. This allows the dehumidifier to be located outside of the indoor garden. Be sure to also purchase the return/intake air attachment (part #310786) to attach ductwork to the air intake and pull moist air out of the garden. This 10 inch flange fits the Dual 105, Dual 155, Dual 205 and Dual 215 only.