欧美一级亚洲一级在线手机观看_国产精品成人制服在三区_精品少妇牲色无码Av_99re6国产精品视频免费观看_完熟60五十路亚洲一区

Type O probe is also called ring yoke probe, it is designed by the principle of magnetic field, used to detect the irregular workpiece of bearings, pipes, vanes etc. When using, put the small workpiece in the ring, magnetizing it by magnetic suspend liquid, the cracks of bar will show out.