"We do windows!" And other envelopes, too-all sizes and shapes, from small coin and jewelry envelopes to business-size, catalog, expandable and larger. DOUGLAS FORMS has all the standard sizes, in a wide array of paper stocks, and can also provide envelopes with custom sizes, custom windows, security tints and self-sticking features. We also carry "packing list enclosed," "invoice enclosed" and other shipping envelope items of all shapes and sizes.