If your office runs QuickBooks, Quicken, or any standard accounting software, this is the envelope your billing workflow was designed around. The #10 double window envelope measures 4 1/8 x 9 1/2 inches and features two precisely positioned clear poly-film windows. Fold your invoice or statement into thirds, slide it in, and both addresses show through automatically. No labels. No handwriting. No printing anything on the envelope itself. The top window displays your return address and the bottom window displays the recipient address, both pulling directly from your printed document.
The flip-and-seal closure means no licking, no sponge, no moisture at all. Flip the bottom tab up, fold the top flap over it, press down, and it's sealed. For offices processing dozens or hundreds of pieces per billing run, that sealing speed difference is real time saved every single month.
Product Specifications
- Size: 4 1/8 x 9 1/2 inches (#10 standard)
- Paper stock: 24 lb white wove, smooth finish
- Windows: Two clear poly-film panels, top and bottom, left-positioned
- Closure: Flip and seal (no moisture required)
- Interior lining: Security tint pattern blocks contents from view
- Color: Bright white
- Compatible with: QuickBooks, Quicken, SAP, and most standard invoice and statement formats
- Ships: Same or next business day
Why Two Windows Make the Difference on Invoice Envelopes
A single-window envelope shows the recipient address only. You still need to print a return address label or pre-print the envelope face for every batch. The double window eliminates that entirely. Your company name and address in the top-left corner of your invoice aligns with the top window. The recipient's billing address in the standard address block aligns with the bottom window. Both show through without any extra steps.
This is why accounting departments, payroll teams, healthcare billing offices, and financial services firms standardize on double window envelopes for recurring mail. The address alignment is built into your document template once. After that, every piece that goes out is consistent, professional, and correct without anyone manually verifying it. You can also slip a standard #8 or #9 return envelope inside alongside the invoice, making it easy to prompt payment back in the same mailing without a separate outgoing piece.
Security Tint That Actually Does Its Job
The interior carries a printed tint pattern that prevents the envelope contents from being readable through the paper when held up to light. For invoices, financial statements, payroll documents, and any correspondence carrying account numbers or payment details, that privacy layer matters. The outside looks like a clean white business envelope. What's inside stays inside until the recipient opens it. Combined with the laser-safe poly-film windows that won't wrinkle or distort under heat, these envelopes run cleanly through high-volume printer and inserter setups without jams or alignment shifts.
Why Serious Billing Operations Order From Us
We've been supplying invoice envelopes to accounting firms, medical billing offices, property management companies, and small business owners since 1997. The customers who stick around aren't just buying an envelope. They're buying the certainty that the window alignment doesn't drift between boxes, the seal holds through postal handling, and the order ships the same day without a follow-up call. No minimums, free shipping across the 48 contiguous states, and bulk pricing that scales with your volume. If you need a high-quantity quote for a recurring billing program, request one here and we'll turn it around the same day. For other self-sealing options across different sizes and formats, browse our full self-seal envelope catalog or the complete double window envelope range.
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