Indigo® Board Back Envelopes provide a secure and professional solution for mailing important documents. Featuring a durable 350gsm board back, a convenient address window, and a strong peel-and-seal closure, they help protect contents from bending or creasing during transit. Finished in classic manilla, these envelopes are ideal for offices, schools, businesses, and home use, making them perfect for sending invoices, contracts, certificates, reports, and other important documents with confidence.