#10 Window Envelopes (4 1/8 x 9 1/2) - 24lb. Bright White - Laser Safe (500 Qty) | Perfect for Checks, Invoices, Letterhead, Letters, Statements | 24lb Paper | 92019-500 Size: #10 Window Envelopes 4 1/8 in x 9  in / 4.125 x 9.5 / 104.775mm x 241.3mm Quantity: Pack of 500 Color: 24lb. Bright White - The standard weight for envelopes, great for everyday business. Is the least expensive white paper, but isn't "cheap" looking. USES: Checks, Invoices, Letterhead, Personal Letters, Statements, Bills, Flyers. Applications: Business Mailings, Direct Mail, Corporate Mailings, Financial Mailings, Personal Mail. Printable on off-set and digital printing presses and some home printers.