Engineering technical specification and design reference for high-grade N52 disc magnets and custom NdFeB rare earth permanent magnet assemblies. Details dimensional tolerances, surface flux density (Br), coercive force (Hcb/Hcj), maximum energy product ((BH)max ~ 52 MGOe), thermal demagnetization coefficients, and protective plating including multi-layer Ni-Cu-Ni and epoxy. Suitable for precision sensors, high-speed brushless motors, magnetic couplings, and industrial holding fixtures.