100 Forever Stamps Stamped Envelopes - #10 Security Self Seal Envelopes (4-1/8 x 9-1/2 inch) 100 PRESTAMPED (with new Forever Stamp) #10 Envelopes, ready to mail All envelopes are Strip & Seal with Security Feature, 4.125 x 9.5 inch envelopes Forever stamps will always be valid for first class postage even if rates change Note: Forever Stamps style may vary