Dual-Window Self-Seal Envelopes (#10) - Featuring a convenient self-sealing flap design, these #10 envelopes are a preferred choice for offices and accounting teams responsible for high-volume mailings. They utilize a permanent self-seal mechanism that forms a secure bond with just a light press, eliminating the tedious step of peeling off an adhesive strip and significantly boosting workflow efficiency. Dual-Window Business Envelopes (#10 Self-Seal) - Designed to display addresses through two windows, these envelopes are frequently selected by businesses of all types when sending invoices, account statements, and general business correspondence. Their clever design allows both the sender's and recipient's addresses to be displayed simultaneously through the windows, thereby reducing the manual effort required for address entry and ensuring the consistency and standardization of mailing information. Weight: 5.79 lbs.