Neodymium Rare Earth Magnet disc - 20mm x 3mm
Geostuff.com.au
$5.95
This rare earth disc has a diameter of 20mm and a height of 3mm. It has a magnetic flux reading of 1810 Gauss and a pull force of 4.3kg. Grade N42
Just one of these is sufficient to magnetically hold a mint container VERY VERY securely.