Du Pont brand Tyvek® Envelopes are lightweight and moisture, puncture, rip, and tear resistant. They can transport bulky or uneven items with reduced risk of the envelope being damaged in transit. Save on postage costs by using lightweight Tyvek® envelopes instead of boxes and cushioning materials. Flaps on Tyvek® Envelopes have strong Peel & Seel® adhesive closures to make it easy to know the envelope is securely closed. Choose from a wide range of sizes, from Tyvek® #10 envelopes to 10 x 13 envelopes, jumbo envelopes, or Tyvek® expansion envelopes.