Envelopes #10: These #10 security envelopes feature a windowless design, making them an ideal choice for small businesses, home offices, and daily mailing tasks. Each pack includes 30 envelopes letter size to cover your regular mailing needs. Security Envelopes: Designed with a premium inner security pattern, these mailing envelopes protect sensitive information, preventing unauthorized viewing through the letter envelopes. Envelopes Self Seal: Featuring a secure self-adhesive strip, these business envelopes provide a reliable seal across the entire width without needing moisture, keeping your documents securely sealed during transit. Bulk Mailing: Measuring 4-1/8 x 9-1/2 inches, these white envelopes are fully compatible with most laser and inkjet printers, allowing for easy and efficient addressing for bulk mailings. Long-Lasting Supply: Crafted from high-quality materials, these envelopes are built to last, making them perfect for high-volume business mailings and providing a long-lasting supply.