I purchased a couple of diff/gearbox plugs last week, bought factory Nissan. The unit I pulled out was factory Nissan complete with a magnet. The units I received were also factory Nissan, no magnet. Seems you need to specify your VIN in order to get the right one, which as curious as the plugs are sold as fitting across GQ/GU. I have never found much residue on the magnets anyway, but it may be important for you.