Business Envelopes # 9 Window 3-7/8x8-7/8-Inch Envelopes-Security Tinted Envelopes-100/Count Number 9 window security tinted envelopes. Envelope is ideal for all business, professional and personal correspondence Security tinted for added privacy and confidentiality Premium 24lb white wove stock. Moisture activated gummed seal Dimension (3 7/8 x 8 7/8