Quality Park #10 Single Window Security Business Envelopes (model QUA21418) are a professional mailing solution for standard business correspondence. Each envelope measures 4-1/8" x 9-1/2" and is constructed from 24 lb bright-white wove stock, giving mailings a clean, professional appearance.

The left-side window (4-1/2" x 1-1/8"), positioned 7/8" from the left edge and 1/2" from the bottom, is sized to accommodate most standard invoice and business address layouts, eliminating the need to address envelopes separately. A security tint using a reflex blue pattern makes it impossible to see the contents even when held up to light, protecting sensitive client information.

The Redi-Seal self-adhesive closure requires no moisture to seal. A double-flap design keeps the adhesive from sticking prematurely — simply raise the lower flap and press to close. These envelopes are made in the United States and arrive 500 per box.