What it is: the 5-foot hose that carries scent from your diffuser into the HVAC duct. Replace it if it is worn, kinked or you need to re-route the installation.

Fits: ARO HOME (0.25 in diameter), ARO PRO (0.5 in) and ARO MAX (0.5 in). All three are 5 ft long; the diameter is what differs, so choose the variant that matches your model.

Connecting to the duct? The ARO PRO and ARO MAX also use the HVAC steel hose connector.