Product Information: Available only in full boxed quantities. Made from 350gsm White Card (White Exterior/Brown Interior), No Windows, Peel and Seal Strip. Packaging Shack’s White Card Envelopes are great for protecting books and DVD’s etc. in transit. Made from a heavy duty card, these envelopes offer more substantial protection than traditional paper . The envelopes are sealed using a peel and seal strip to ensure it remains sealed during transit.