What's the difference between Level 1 and 2 and 3 masks?

What's the difference between Level 1 and 2 and 3 masks?

https://sante-group.com/what-is-the-difference-between-level-1-2-3-masks/

As per the test results, masks are rated numerically, on the barrier performance of the material.

Level One: Low barrier protection. Only for general use, not used for aerosols, spray or fluids.

Level Two: Moderate barrier protection. Use for low to moderate levels of aerosols, spray and/or fluids.

Level Three: Maximum barrier protection. Use for high risk of fluid, spray and/or fluids.