What product specs for letters do you have available? 8.5” x 11” B&W Document Specs 60# text/89gsm paper #10 2-window outer envelope 8.5” x 11” Color Document Specs 60# text/89gsm paper #10 2-window outer envelope Related articles If I print my letter double-sided is that considered two pages? What does the address_placement parameter mean? How can I export my letter data? What do the different US Mail Strictness Settings do? Are Lob processes HIPAA compliant?