Use this envelope with ProSeries Software, TaxSimple, HowardSoft, Alpine Data, TaxWise and TaxWare Systems. This "Income Tax Return" window envelope allows you 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. This 9 1/2" x 11 1/2" envelope is constructed of 28lb paper.