... time and all-round service Tile/Segment Neomydium/NdFeB Magnet:1) Superior magnetic properties than other magnets2) ... devices4) Mostly an iron based alloy,,NdFeB type rare earth magnet is much more prone to surface ... oxidation or rust,and elimination.Users should consider magnet coating,plating or suitable surface treatment.5) ... temprature.8) Types:N30,N33,N35,N38,N40,N42,N30M,N35M,N38M,N40M,N27H,N30H,N33H ...