Olson Mask for PPE With Optional Filter Pocket : 13 Steps ...
The pattern only has two pieces, the main mask, and the pocket pattern (optional). You'll want 2 matched pairs of the main mask, one for the front and one for the inside. For the pocket you will want 1 matched pair of your inside or a contrast fabric. If you are using an old super soft t-shirt, that usually goes on the inside parts.