This is the matching envelope for LIFE's White Writing A5-size pad. It is made of the same white "laid" paper as the pad.

10 envelopes, size C6 (113x162mm, or just under 4.5x6.5 inches). It is designed for an A5 sheet folded in half. The flap does not have adhesive - to close, use tape, glue or a wax seal.

It also has an inner lining - a nice touch.