Postage-saving, lightweight multi-layered paper mailer is significantly stronger than traditional paper designs. Moisture resistant finish protects contents from spills and inclement weather. Perforated Flap-Stikļæ½ closure is easy to seal and open. Expansion safely accommodates bulkier documents and items. Envelope Size: 10 x 13; Envelope/Mailer Type: Expansion Mailer; Closure: Self-Adhesive; Trade Size: #97.