A-class EVA is environmental protection material (new material foaming).
B class EVA is half environmental material (half new material and half recycled material).
C-class EVA is ordinary material (recycled material).
EVA mainly looked at the stomata distribution and hardness on the surface.
There are few holes on the surface of a-class EVA (basically none).
There will be some holes in the surface of b-class EVA.
There are many holes on the surface of c-class EVA.