Masks are our first line of defense against invading pathogens, so it is important to take proper care of them when they are not being used. Our mask envelopes help ensure that your reusable mask stays in good condition and lasts as long as it is meant to. Made of 100% cotton, the DET Mask Envelope features the same anti-bacterial and water-repellent treatment as the DET30. Buy our mask envelope online today and keep your DET30 cotton mask clean and fresh on the go.