... *20mm 2)in good quality and price 3)has strong magnetic force Large Ring magnet N35,N38,N40,N42,N45,N48,N50 ... (as per the requirements).5. NdFeB magnet has super strong magnetic force and high intrinsic coercive force.6, With precise tolerance ... .Application for NdFeB magnet:Magnetic separator, Sensors, Wind generators,Vibration motors,DC motors, Servo motors ...