What venting system should I use for the dryer?

Use only a heavy metal vent (4-inch diameter)—do not use plastic or metal foil vents. Rigid metal vents are recommended for best performance, though flexible metal vents are acceptable only if accessible for cleaning and must be fully extended and supported. Use clamps to seal all joints and do not use duct tape or screws to secure the vent. (Page 12-13)