On the left is the magnetic sweep I just bought. It was advertised as 17" wide. Actually, the magnetic part is 14.5". Outdoors, narrower good. It will keep the magnet at a more uniform distance above uneven ground.
The silver thing to the right of the sweep handle is a telescoping pocket magnet. To the right of that is the wood handle I made for the 6"-wide magnet I've used for 40 years. In front is a 6" parts bowl I bought on impulse the other day.It resembles a loudspeaker with a round 3" magnet for its base. Even on a non-ferric surface, the weight of the magnet provides stability, and you have a magnet handy in case you drop a screw in the grass.
The bowl holds 33 nails that the sweep picked up in the carport, in a welcome-mat sized space in front of the door to the pump house, built when they changed from wind power to electricity in 1920. The different degrees of rusting indicate that they were dropped over a period of decades. It's weird that I never checked that spot with my 6" magnet. Otherwise, the only thing the sweep found was a roofing nail under a bush. I guess I've been pretty thorough with my 6" magnet.
I'm bound to lose a bicycle part in the grass. The sweep will search more efficiently than the other magnets.