5,000 Self Seal Double Window Envelope Item #CE15149S Top Window: 11/16" x 4-1/8", Position: Left 1/2", Bottom 2-1/2". Bottom Window: 1-1/16" x 4-1/2", Position: Left 7/8", Bottom 1/2". Overall Size 3-3/4" x 8-5/8 Mail invoices, payments and newsletters to clients, vendors and staff members. With single and double window envelopes, including self-seal envelopes for even easier mailings, you can quickly prepare and ship documents across town or around the world. Browse our complete collection of business envelopes ? and choose the right solution for all of your company's needs.