1999 US Both Blue & Yellow Mast USA Flag First Day Covers Artmaster Cachet.  Scott Catalogue #U642 and U643.

U 643 is sized 8 7/8 x 3 7/8" (Size 21)  U642 9 1/2 x 4 1/8" (Size 23)

Both in Excellent Condition  As Seen in Photos

Shipps by USPS Mail