Quality Park #10 Left Window Security Tinted Envelopes with a Self Seal Closure for Standard Business Mailings, 24 lb. White Wove, 4-1/8 x 9-1/2, 500 per Box (21418) SINGLE WINDOW ENVELOPE: Instead of printing both the contents and the envelopes with an address, use the window to reveal pertinent information. Display the receiver addresses through the window. Positioned to fit most invoice address layouts, this left side window envelope not only saves time but also makes sure the document is delivered straight into the customer's hands! ENHANCED PRIVACY FEATURES: Protect sensitive client information with these security tinted envelopes. The reflex blue pattern lining the envelope's interior makes it impossible to see the details of the contents, even when held up to the light. Mail invoices, statements and other important documents with confidence. REDI-SEAL SELF ADHESIVE CLOSURE: With the Redi-Seal closure, envelopes do not require moisture to seal. The unique double-flap design keeps the gum from sticking before use. Simply raise the lower flap and press to seal. 500 ENVELOPES IN EACH BOX: ideal for both everyday office use and bulk mailings, each box of Quality Park #10 Left Window Security Tinted Envelopes provides a long lasting supply for your Standard Business Mailings!