Reduce the risk of dryer fire by keeping the dryer duct clean and free of lint. Acts as a secondary lint trap for electric clothes dryers – not intended for gas dryers. Fits all 4″ dryer ducts. Installs easily onto the dryer transition duct collecting additional lint to help eliminate unwanted and excess lint within the duct. Air passes easily and without obstruction, allowing the dryer to run more smoothly and efficiently. Clear door gives unobstructed view of lint screen. Includes: 1 lint trap unit, 1 removable lint trap screen, (2) 4″ metal clamps, and installation instructions.