permanent-magnet meter

例句：

1. 1.This permanent magnet meter is very accurate and easy to use.
   这个永久磁铁表非常准确且易于使用。
2. 2.The permanent magnet meter was used to measure the strength of the magnetic field.
   永久磁铁表被用来测量磁场的强度。
3. 3. The permanent magnet meter can be used to detect the presence of a magnetic field.
   永久磁铁表可以用来检测磁场的存在。