Make a bold statement with our 155x155 mm black envelopes, crafted from 120gsm eco-friendly eucalyptus paper for a recyclable, sustainable solution. Featuring a gummed flap for secure sealing, these square envelopes are ideal for Christmas cards, birthday cards, and special occasions. Royal Mail letter-compatible, contact our team for Custom Printing options for these 120gsm black gummed envelopes.