There are 4 grades of masks.

• The first grade of loop mask is intended for civil use.
• The next grade is called Level 1 or Medical Loop Mask. A medical loop mask filters ≥ 95% of particles and is what is typically worn in a medical environment by nurses and doctors.
• The last two grades are Level 2 and Level 3 Surgical Loop Masks.

These both filter ≥ 99% of particles, which means they are intended to allow filtration of fluids, including blood. This is what is typically worn by a surgeon.

The difference between a Level 2 and a Level 3 Surgical Loop Mask is that Level 2 typically protects against low to moderate levels of aerosols, sprays and fluids wherein a Level 3 grade typically protects against exposure to heavy levels of aerosols, sprays and fluids.