What is the difference between N95 and KN95 masks?

Both KN95 and N95 masks filtration are tested to filter at least 95% of particles that are 0.3 micron in size.  The difference is this test is performed at different flow rates for each mask.  Most NIOSH-approved N95 respirators will have two headband straps, not ear loops. However, a few NIOSH-approved models are approved with ear loops because the loops are secured behind the head with a non-removable fastener. 

Unless a mask was submitted to NIOSH and tested and approved, it can’t be sold in the US as an N95 mask under any circumstance. One of the main differences is that while both N95 and KN95 standards require external testing before approval, only NIOSH tests masks again in US government laboratories to assure that the masks actually match the external testing results. For KN95 masks, the testing is performed only by the manufacturer because not every country has a test facility like NIOSH that independently tests the masks. So, in theory, a manufacturer could fudge their test results when they send the report into the certifying agency and get approval, even though their mask didn’t pass. This is evident by the number of fake products identified by NIOSH, which have been produced by some manufacturers in China. The Emergency Care Research Institute (USA) tested Chinese KN95 masks and found that up to 70% of masks tested by them do not meet minimum standards. Because NIOSH actually inspects the manufacturing facilities of N95 masks in person (even in China), you can usually be assured that manufacturers who produce NIOSH approved N95 masks, will also produce a KN95 mask that is manufactured under the same quality system. You should only purchase KN95 masks listed by NIOSH or from companies that also produce N95 masks.