LOWER/ EXHAUST HOSE 12" X 25' Unlike many we have seen this is a very sturdy hose and will tolerate fumes for a longer period of time before degrading. PORTABLE BLOWER VENTILATOR FANS 25 Long Ducting for 12" Diameter Fan ( axial blower )Ducting easily converts Blower / Fan (sold separately) to an exhaust fan with convenient, flexible ducting. Ducts include quick-connect coupling for easy blower attachment. Ducts are made with 2-ply reinforced polyvinyl.