The emery hardens to bear to whet a ground of ping to check before acceptance the standard

A, color:
The color is even, don't divide the color.

Two, surname degree of hardness:
≥ 75

Three, whet the pit length:( bear to whet sex)
25 mms of ≤

Four, the anti- presses the strength:
7 divas:70 Mpas of ≥
28 divas:80 Mpas of ≥

Five, neat degree in ground:
The 2 ms keeps the deviation of allow of hour of the Chinese foot check:4mm