Amazon.com : 55 3 ⅝ x 5 ⅛ White RSVP Small Envelopes - A1 - For Weddings Response Cards, Baby Showers, Thank You Notes, Photos and any 3” x 5” inserts -
Amazon.com : A6 Blank Invitation and Card Envelopes, Square Flap Gummed, White, Pack of 50, Thick 70# Paper, (6-1/2 x 4-3/4 inches) : Office Products