Poly String & Button Booklet EnvelopeHeavy-duty poly envelopes reisist tears, repel moisture and are available in bright translucent colors for easy organization. Gusset expands up to one and a quarter inches to accommodate bulkier materials. Heavy-duty string and button closure is designed for everyday use. Acid free, PVC free and archival quality. Horizontal orientation. Envelope Size: 11 5/8 x 9 3/4; Envelope/Mailer Type: Expansion; Closure: String and Button.