ComplyRight® Jumbo CMS-1500 Health Insurance Claim Form Envelopes help prevent processing delays by allowing the sender to load the envelopes without folding the related forms before mailing them. Each envelope features a security lining to help ensure your patients' private information remains confidential. Preprinted face, self-sealing square flap and return address window provide additional processing convenience. Designed specifically for CMS-1500 Health Insurance Claim Forms. Accommodates Up to 50 Unfolded CMS-1500 Forms. Seam Type: Side; Flap Type: Square; Security Tinted: Yes; Opening: Open End.