First Class Envelopes
Window envelopes for tax returns and official documents.
- 9″ x 12″ 1st Class envelopes
- Expanding envelopes and more

Official First Class Mail envelopes make it easy to mail tax returns and important documents with ease!
Double Window First Class Envelopes
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First Class Envelope, Landscape Style with Double Windows
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First Class Mail Envelope with Offset Windows
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Double, Center Windows First Class Mail Envelope
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Stars & Stripes Tax Envelope – Double Window
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First Class Mail Envelope with 2 Top Windows
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First Class Mail Envelope, Landscape style with Alternate Windows – 9-1/2 x 11-1/2
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First Class Mail Envelope, Portrait Style with Alternate Windows
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First Class Mail Envelope, Landscape Style with 2 Windows – Green
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10 x 13 First Class Mail Envelope with Alternate Double Windows
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First Class Mail Envelope with 2 Center Windows – Blue
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First Class Mail Envelope – 6 x 9
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Large Landscape Envelope with Double Windows V2
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First Class Envelope, Landscape Style with 2 Windows
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First Class Mail Envelope with 2 Top Windows
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First Class Envelope Portrait Style with 2 Windows – Green
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Blank Envelope – Portrait Style with Double Window
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Oversized First Class Mail Envelope, Landscape Style with Alternate Windows
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Blank Envelope with Alternate, Double Windows
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Large Landscape Envelope with Double Windows
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Fist Class Mail Envelope, Landscape Style with Double Windows
Single Window First Class Envelopes
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Single Window, Portrait Style First Class Mail Envelope
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Income Tax Return Envelope with 1040 Window
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Important Tax Information Envelope with Window
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First Class Envelope – Portrait Style with 1 Window
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Income Tax Return Envelope with 1040 Window
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First Class Envelope – Portrait Style with Single Window, Green
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First Class Envelope – Portrait Style with Center, Single Window
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First Class Mail Envelope, Portrait with Single Center Window, Green
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Landscape Single Window First Class Mail Envelope
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Stars & Stripes Tax Envelope – Single Window
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Patriotic Tax Envelope with Window
Software-Compatible Tax Envelopes