Quality Park, #10 1/2 Health Form Security Envelope, Gummed, White, 4.5x9.5, 500 per box (21432) PROFESSIONAL FINISH: Bright White paper makes for a fresh, clean appearance GUMMED FLAP: Provides users with ease of mind that their contents will stay securely closed CMS-1500-Designed to use with Insurance Form CMS-1500 DURABLE: Heavyweight 24-lb. paper stock ensures no rips or tears SECURITY TINT: Offers more privacy so important information is protected from prying eyes