Quality Park #8-5/8 Double-Window Envelopes (3-5/8 in x 8-5/8 in) have layered privacy features to keep checks safe; security tints & perfed Reveal-N-Seal self seal envelope closures prevent tampering These tamper-evident envelopes for checks feature Reveal-N-Seal perforations along the envelope flap to show evidence of mail tampering; seal quick to save time and send checks securely Double window security envelopes shield id numbers and private data with a security pattern, even when held to light; top window: 7/8" x 3-1/2"; bottom: 1" x 4"; envelope: 3-5/8" x 8-5/8" Our dependable patented envelope design has a unique flap that folds up and into place for a firm seal that won't close and stick prematurely; plus, no peel-strip waste to clean up! Stock up on value-packed boxes of 500 24 lb white wove, double-window, tamper evident security envelopes for your secure monthly payroll and accounts payable mailings