This accessory allows a limited amount of ductwork to be attached to the intake on Quest Dual dehumidifiers. This allows the dehumidifier to be located outside of the indoor garden. Be sure to also purchase the supply air attachment (#310784) to attach ductwork to the air outlet and send dry air back into the garden. This 12 in flange fits Dual 105, 155, 165, 205 and 225 and Series 5