What is IRS form E 182 W
This is the code used by the IRS for a 9½ tall by 12½ wide, 32 lb. light brown kraft window envelope.
I'm holding one in my hand right now. On the front lower right quadrant there's a 3 ¾ tall by 5 3/8 wide plastic window to enable the display of an address on a page placed inside. On the reverse side, there's a contact seal strip along the long edge at the top.
The following appears on the envelope's reverse side at the lower right hand corner: E-182 W (REV. 3-2000) Cat. No. 64288W