#9 Double Window SELF SEAL Security Envelopes - 550 Per Box - Designed for QuickBooks Invoices, Business Correspondence, and Legal Documents - Security Tinted - Peel & Seal - 3 7/8" x 8 7/8" - 24 LB IDEAL FOR INVOICES: designed specifically for invoices and legal documentsperfect invoice envelopes for QuickBooks invoices and statements as well as other computer-generated invoices; dual windows placed in an ideal location for invoice address information PREMIUM QUALITY: our window envelopes feature a high-quality security pattern, premium 24 lb. paper, and a superior adhesive seal BEST VALUE: each box comes with 550 envelopes, not the standard 50050 bonus double window envelopes included with each order! EASY TO USE: a speed seal flap and ultra-strong adhesive make mailing easysimply peel the strip away and press the flap down for a permanent seal that wont rip open or tear while in transit! MAXIMUM PROTECTION: our high-quality security pattern and heavy paper stock protect your numbers, data, and correspondencemail your checks and advertisements with confidence knowing that your sensitive information will remain private