To determine the correct mask size for your facial structure, we recommend taking exact measurements using the method described below. This is the most accurate way to determine your correct size.

1. Measure from the bridge of your nose to the tip of your chin. It may be helpful to have a friend assist you. *See fig.1

NOTE: Use a rigid measuring tool and measure in a straight line up and down. *See fig.1 Measuring from the height of the bridge of your nose (usually just below your eye line) down to the tip of the chin. For accurate results, do not use a flexible measuring device such as a sewing measuring tape or a string. Also, do not measure past the tip of your chin.

2. Match your measurement with the given sizes below to find the correct sizing for you. You can also use the different approximate facial types to help you find the best fitting mask. *See fig. 2 – 4 below.


A proper fit is key to efficient filtration and prolonged comfort. There are a few tips and tricks to help fit your mask properly. *See fig.2 below.

1. When applying your mask, place the top most part of the mask on the very top of your nose, then lower to cover your mouth and chin. Finish by fastening the strap(s) in a comfortable position.

TIP: If you feel pressure on the top of your nose, fasten the strap in an “upward X” position. Vice versa for pressure on the bottom of your chin.

2. A proper seal is only required on the filter, not the mask shell. *See fig.5 As you notice, the filter (blue) is creating a seal on the users face while the mask shell has some slack. This is acceptable. As long as the filter is creating a seal, the mask is deemed effective.

*RZ filters are designed to match your chosen mask size, i.e. a Medium (M) filter fits a medium mask, a Large (L) filter fits a large mask, and an Extra Large (XL)