An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card. Up until 1840, all envelopes were handmade, each being individually cut to the appropriate shape out of an individual rectangular sheet. Most of the over 400 billion envelopes of all sizes made worldwide are now machine-made.
4x4 Square Gummed Diamond Flap Envelopes - 101mm x 101mm