These expandable peel and seal envelopes from JAM Paper offer the protection of DuPont™'s heavy duty Tyvek polymer. Get the protection your business and personal items deserve with these premium envelopes that are perfect for mailing invoices, checks, cash, and a variety of other uses. They are also great for storing precious items for safe keeping! The straight flap protects the contents inside as the peel and seal closure offers a quick and easy way to secure them. They have a semi-smooth textured finish and offer unmatched tear and water-resistant quality convenience. Tyvek is a registered trademark of DuPont, an established chemical company that develops the powerful polymer used to make these envelopes. Details: White Available in multiple sizes Straight flap with peel and seal closure Expandable Tear and water-resistant 10% recycled materials 100 envelopes Tyvek polymer