DEFLECTO DAF1 Skinny Duct(TM) Telescoping Aluminum Vent (18"-31") 4" oval;Adjustable 18" - 31" DAF1 Skinny Duct(R) Telescoping Aluminum Vent (18" - 31") DAF1 Skinny Duct(R) Telescoping Aluminum Vent (18" - 31") skinny duct(r)