Ring magnet( permanent magnets) has high-consistency, low-zero gravity, high working temperature and the highest temperature to 230degree.

 Precision of permanent magnets( ring magnet)
1)Demensional tolerances can be controlled less than in the +0.1mm
2)Verticality can be controlled less than the 0.01mm
3)Concentricity tolerance of cylinder can be controlled in the 0.01mm
4)Inner hole tolerance can be controlled in the +0.01mm.