Breathable valve face mask is KN95 mask with valve which can be used by medical workers in the department of infectious diseases. Its effect is similar to N95 mask.
KN95 masks are international standard masks of the same type, and N95 is the American standard. They all mean that they can block 95% of non-oily particles. N means non-oil resistant particles. For some oily particles The occlusion effect is not enough. Non-oily particles such as bacteria, viruses, and dust have good effects and can be used.