N95 is a 5 layer mask. N: This is a Respirator Rating Letter Class. It stands for Non-Oil meaning that if no oil-based particulates are present, then you can use the mask in the work environment. Other masks ratings are R (resistant to oil for 8 hours) and P (oil proof). 95: Masks ending in a 95, have a 95 percent efficiency. Masks ending in a 99 have a 99 percent efficiency. Masks ending in 100 are 99.97 percent efficient and that is the same as a HEPA quality filter.
