Confidential First Class Mail Envelope. Use this Double Window First Class Envelope to mail any Confidential Documents using a compatible software slip sheet or custom mailing insert. Specifications:Style: PortraitSize: 9 1/2" x 12"Top Window Size: 1 1/8" x 4 3/4"Top Window From Left Side: 13/16"Top Window From Bottom: 7 3/8"Bottom Window Size: 1 3/4" x 4 1/2"Bottom Window From Left Side: 1 5/16" Bottom Window From Bottom: 5 1/16"Weight: 24#Material: White WoveInk Color: BlueFlap Opening: ShortSeal: Peel & Close, Tamper Evident