Tyvek First Class Envelope with Pressure-Seal Flap

Use this expandable "First Class" envelope for mailing large tax returns and reports of up to 100 pages. It features a "Peel-and-Seal" flap for easy mailing. Constructed of durable Tyvek material, this 10" x 13" envelope is waterproof, tear-resistant and lightweight to help lower your shipping costs.