... good quality and price 3)has strong magnetic force Large Ring magnet N35,N38,N40,N42,N45,N48,N50,N52(M,H ... ,SH,UH,EH Largest size:OD170mm Ring shape with hole High coercive forceNeodymium Ring Magnet with N35,N38,N40,N42,N45,N48 ... centigrades to 200 centigrades.3. Can be magnetized through thickness,Radial,Multipoles...4. Coatings: Ni, Zn, Ni-Cu-Ni,Epoxy, gold ...