Columbian CO297 (#10) 4-1/8x9-1/2-Inch Poly-Klear Left Window Self-Seal Security Tinted White Envelopes, 500 Count Envelope is ideal for all business, professional and personal correspondence. Poly-Klear left window position eliminates need to address envelope. Convenient and secure self-sealing Self-Seal closure. Simply raise lower flap and press top flap down for a quick seal. Security tinted for added privacy and confidentiality. Premium 24lb white wove stock. (#10) 4-1/8" x 9-1/2" 500 envelopes