Heavy-duty poly envelopes resist tears, repel moisture and are available in bright translucent colors for easy organization. Gusset expands up to 1 1/4″ 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/Mailer Type: Interoffice; Envelope Size: 9 3/4″ x 11 5/8″; Closure: String & Button; Flap Type: Hub.