C6 Envelopes
Worth knowing what this size is not: an A4 sheet folded twice is DL, not C6, and trying to fit one here gives a bulging envelope. C6 matches A6 card stock, which is why it is the standard for greeting cards, invitations and compliments slips. Pastel and coloured stock is common at this size because the use is personal rather than transactional. See envelopes, DL envelopes and business cards.
