HERKKA #10 Double-Window Security Envelopes 500-Pack White 24 lb — Self-Seal, Printer-Friendly

HERKKA #10 double-window security envelopes are pre-tinted, self-seal mailers designed to protect printed contents while displaying both sender and recipient addresses.

These envelopes are sized for standard business documents—invoices, statements, returns, and checks—and come in a bulk 500-pack to support frequent mailing needs. Constructed from 24 lb white paper with an internal security pattern and two transparent windows, they simplify mailing by eliminating separate address labels and reducing handling time. The self-seal strip offers a fast closure without additional adhesives, and the design is compatible with most laser and inkjet printers.

How do these envelopes keep information private during mailing?

The interior security tint obscures contents from casual viewing while still allowing address blocks to show through the two windows. This reduces the chance of sensitive details being seen through the paper and helps preserve confidentiality for billing and financial documents.

• Dense printed security pattern inside prevents readability through the paper
• Two windows positioned to reveal printed sender and recipient addresses only
• 24 lb paper weight balances durability and feed compatibility

Will these fit standard invoices and QuickBooks forms without folding or rework?

The 4-1/8 x 9-1/2" dimensions match the common #10 envelope size used for many accounting and billing forms. With proper document positioning and folding, QuickBooks and other invoice templates align with the dual windows so addresses print correctly without extra trimming.

• Standard #10 size fits most statement and invoice formats
• Two-window layout supports both sender and recipient fields
• Works with typical fold patterns used by accounting software

How simple is it to seal and prepare large mailings?

The envelopes feature a self-seal adhesive strip that closes quickly and securely—no licking, water, or tape required. This speeds up batch processing and reduces setup time for mass mailings while producing a reliable closure that resists opening during handling.

• Peel-and-seal strip enables fast, consistent closure
• Strong adhesive holds across the full flap width
• Box of 500 supports high-volume mailing without frequent restocking

Are these envelopes printer-friendly and suitable for everyday office use?

Yes — the smooth 24 lb paper surface is formulated for use in most laser and inkjet printers, minimizing jams and enabling clean address printing. The white finish reproduces toner and ink clearly, making addresses and return information easy to read.

• Smooth stock compatible with home and office printers
• White exterior gives sharp contrast for printed text
• Bulk packaging reduces purchase frequency for busy offices

Who is this product for? Small businesses, accounting departments, law offices, non-profits, and busy home offices that regularly send invoices, statements, checks, or return forms will appreciate this pack. If you need a ready supply of professional-looking envelopes that protect sensitive content, simplify printing with two windows, and speed up sealing for batch mailing, this 500-count box from HERKKA is a practical choice.