No. 10-1/2 Healthcare Claim Form Envelopes are perfect for CMS-1500 and other insurance forms. Reflex blue pattern protects sensitive information by obscuring the details of the contents even when held up to light. Envelopes feature a self-sealing, Redi-Seal closure. Simply lift the bottom flap and press to the top flap for an instant, secure seal. 24 lb. white wove envelopes and side seams add a modern, clean touch to professional mailings. 4-1/2" x 9-1/2" envelopes include a single window (1" x 4-1/2") positioned 4-1/4" from the left edge and 1-9/16" from the bottom. Window creates space for a name and address without revealing other personal information on the claim form.