Use this double window envelope for convenience when mailing checks. The envelope has a reverse flap to be used with inserting machines. To confirm compatibility with your checks, order a free sample.Specifications:Size: #10Top Window Size: 1" x 4"Top Window From Left Side: 1/2"Top Window From Bottom: 2 5/8"Bottom Window Size: 7/8" x 3 3/4"Bottom Window From Left Side: 3/4"Bottom Window From Bottom: 1"Weight: 24#Material: White WoveFlap Opening: ReverseSeal: Moisture