Security Tinted Insurance Claim Form Envelope, Commercial Flap, Gummed Closure, 4.5 X 9.5, White, 500-boxQuality Park #10 1 2 Healthcare Claim Form Envelopes are for CMS 1500 and other insurance forms. The reflex blue pattern protects sensitive information because it obscures the details of the contents, even when held up to light. These 24 lb white wove envelopes can be used for professional mailings; side seams provide a more modern, clean look. Seam Type: Side; Flap Type: Commercial; Trade Size: #10 1 2; Security Tinted: Yes.