Business Source 36680 Double Window Envelope, No. 9, 3-7/8" x 8-7/8", White (BSN36680) Pack of 500No. 9 envelopes feature security tint and double windows and are compatible with most standard letter size, computer generated invoices and statements. The 1 3 16" x 3 1 2" top window is positioned 3 8" from left and 2" from the bottom of the envelope. The bottom window (1" x 4") is 3 8" from the bottom. 24 lb. General Information Manufacturer: Business Source Manufacturer Part Number: 36680 Brand Name: Business Source Product Name: No. 9 Double