Since classified insurance documents require a special level of durability and confidentiality opt for First Class insurance claim envelopes. With First Class insignias on the white wove paper the forms are sure to arrive in a timely manner. When they do they ll be tightly secured by the self-sealing adhesive until the recipient opens the parcel. He or she can glance at the single poly window to determine the contents. Seam Type: Center; Flap Type: Cheese Blade; Trade Size: #10; Security Tinted: No.