Business Source No. 10 Window Business Envelope, 500/BX, White (BSN04468) Box of 500No. 10 business envelopes with windows are good for everyday mailing. Traditional design includes white wove 24 lb. stock, diagonal seams and fully gummed, V flaps. See through window is located in the bottom left corner and measures 4 1 2" wide x 1 1 8" high so the recipient's address on the documents inside is easy to see. General Information Manufacturer: Business Source Manufacturer Part Number: 04468 Brand Name: Business Source Product Name: No.