Item Number 80922 Use this "First Class Mail" double window envelope with a Peel and Close flap to easily mail any tax return or report. A blue interior tint adds security while the cellophane window allows the taxpayer name and address to clearly show through. Add a professional touch by imprinting your return address on the back flap if you choose. This 9 1/2" x 12" envelope is constructed of 28lb paper Envelope Size: 9 1/2" x 12" Top Window Size: 2" x 6" Top Window From Left Side: 2" Top Window From Bottom: 7 3/16" Bottom Window Size: 2" x 6" Bottom Window From Left Side: 2" Bottom Window From Bottom: 4 13/16" 28lb white wove stock