Flexible Dryer Vent Hose: Dryer duct hose is a flexible vent hose made of high quality flame retardant aluminum that measures 4" (diameter) x 1.5m (length) when fully unfolded. you can install any 4" vent pipe or 4" flexible dryer hose Easy to Install and Better Locking System: The 4-inch vent cover connector features a secure twist lock, you can just turn the connector to lock it down, make more and airtight seal between the hose and the wall duct, don't need to worry about the hose off easily Quick Connect & Disconnect: With its innovative twist-lock mechanism. Excellent for quick connect/disconnect of dryer vent hose, this makes it more convenient to clean out any lint or debris that may accumulate in the ducting Perfect Connector:This dryer vent coupler is 7 x 7 inch. Fits 4 Inch Tubes. Works well for covering up a hole in the wall for the dryer vent. Makes the closet wall look clean and make your laundry room look professional finished Abundant Applications: Suitable for residential air duct solutions; Widely used in bathroom venting, dryer ventilation, planting room, laundry room, laundry closet, table saw dust, wall exhaust vent, ceiling or warmhouse air circulation, etc