I found an old boom bass speaker on the side the road, and grabbed it for the magnet. It's over 5 inches diameter, and attached the part that held it to the speaker to a piece of 1 1/4" wooden closet rod, the right length to comfortable hold just above the ground. It's a strong magnet, and works well to sweep an area for light metal objects. It also picks up lots of metal dust too tho, but i guess any magnet would.