Strong Neodymium Magnet Super Powerful Search Magnets Hook Magnetic Fishing 

Ordinary neodymium magnets only use one side of their magnetic field to stick to metal which means they’re only using half of their available strength.

However,if add a steel cup, the other pole of the magnet to be used which increases the strength of the magnet to much higher than that of a normal neodymium magnet but also makes the other side magnetically weak.

If the highest possible pull force is required, then neodymium cup magnets are the answer to your magnet needs

In sunny weather, call your friends go to Treasure hunting! 

How wonderful it will be to enjoy the sunshine while enjoying the salvage from the water!

The link detail : 

1pcs deep sea salvage magnet