Lorica masks are made with a single layer of polyester/spandex with a center seam. Aerosols do not visibly penetrate them, and they have been tested to filter dust. I don't feel comfortable making the claim that my masks are going to make you impervious to any virus, but maybe they'll give you a little more courage to face the day. If they at least make going outside with a face covering one iota less dreadful, and one iota more powerful, I hope they're something worth making.
All masks have been washed once, but do consider washing a second time before wearing (especially if you are sensitive to certain detergents: I use Tide).
To get the best fit, I recommend measuring your face from the bridge of your nose to the back of your earlobe. Match that measurement to the mask's, rounding down. I wear a S, and my distance is almost exactly 6.5". Luke wears a M, and his distance is about 7". If you're between sizes, size down: it's better to get a tighter seal than to have it gapping around your face, they do stretch.
Please be advised that masks are not returnable.