Double Window Security Tinted Invoice & Check Envelope, #8, White, 1000/Box.Double window design eliminates the need to print on envelope. Wove finish adds a professional touch. Blue security tinting ensures greater privacy. Envelope Size: 3 5/8 x 8 5/8, Envelope/Mailer Type: Business/Trade, Closure: Gummed Flap, Trade Size: 8 5/8.