Tyvek Lunch Clutch What is Tyvek®? Tyvek® is a high-density polyethylene nonwoven fabric uniquely developed by DuPont in the United States. It is a lightweight, breathable, water-resistant, and strong material. Material: Outer: High-density polyethylene Lining: Aluminum/foamed polyethylene Approximately 20cm wide, 25cm high, and 12cm deep. I took it out of the bag to take photos, and there are some color irregularities on both sides. It's new, but I've listed it as "Like New". Please refrain from purchasing if you are concerned.