Perfect for mailing bulky items. • Convenient pull tab tear strip for easy opening. • Finally, a flat mailer that expands to fit and protect its contents. • Due to its patented designs, Conformer® Expansion Heavy Gauge Paperboard Mailers can be used to ship items ranging from thin paper documents to perfect bound books and three ring binders. • Expands on all 4 Sides. • Attractive white mailers provide a professional presentation. • Features easy-to-use peel and seal closure.