Specifications: the white board magnet with colour plastic ABS,size Dia20mm,30mm,40mm. others permanent magnet for Stationery,Gifts,White Board, ferrite magnets (ceramic magnet)with paint red and bule "N ,S" for education: Bar 30*6*4mm Bar 50*8*6mm ,Bar 35*9*6mm ,Bar 105mm*13mm*8mm ; horseshoe (U type) 30*30*8*6mm ,50*40*8*8mm,etc.STRONG