Ideal when you need a little more space. The strength of DuPont™ Tyvek® envelopes provides a great alternative to boxes and other bulky packaging materials to help reduce your mailing costs. Just stuff and seal. Recommended for mail consolidation or larger items, such as binders, oversized files, books, spare parts, apparel, videos and more. A wide range of sizes are available, with gusseted sides ranging from 1.25" to 5" (3.2 cm to 12.7 cm) maximum capacity.