Heavy duty board back envelopes in white and manilla, made using 1000 micron backing board and a heavyweight face paper to ensure protection when posting bendable items. - These envelopes are boxed with their flaps folded down. - These envelopes have external side seams - One of the most secure ways to seal an envelope, peel away the release tape from the flap to reveal a strip of latex and press down to form an instant bond.
