https://www.meank-magnet.com/products/countersunk-neodymium-pot-magnets.html Product Category: NdFeB pot magnets/holding magnets/ countersunk magnets Product Features: rare earth magnet pot, strong magnet pot, powerful magnet pot Available Grade: N35-N54 Surface Treatment: NiCuNi, Zn, Cr, paint-coated.....All Rights Reserved