Envelopes.com A1 Invitation Envelopes (3-5/8" x 5-1/8"), 70 lb

For those occasions calling for a dainty announcement envelope, the A1 (3-5/8 by 5-1/8 inches) is your ideal choice. This diminutive envelope is the smallest of its kind allowed through the mail! The A1 envelope is a social and invitation-type envelope; its dimensions make it the most common-sized envelope used for RSVP and announcement purposes. Featuring an attractive square flap, the A1 fits inside all other "A" envelope sizes.