Our AIR-TIP 2-1/2in Magnetic Utility Nozzle has integrated magnets that catch metal hardware, preventing damage to bags and filters inside of a wet/dry vacuum. The magnetic strips are located on the front and back of the vacuum tool to catch metal hardware before it gets inside the vacuum. The 2-1/2in diameter allows more debris to flow into the vacuum than smaller diameter tools. The black zinc coating on the magnets prevents rust long-term. The MILWAUKEE AIR-TIP Magnetic Utility Nozzle is compatible with only 2-1/2in diameter hose ends and is part of the AIR-TIP family of Trade Focused Vacuum Accessories.