Blue Summit Button and String Envelopes are durably constructed and designed for re-use, crafted with heavyweight 28lb. manila stock paper making these envelopes a great choice for inter-office mailings These Interdepartmental Envelopes have a string and button closure and can store documents up to 10" wide by 13" long Pre-printed lines alloe users to sign their name and department of origin or receipt Space is maximaized with five columns and narrow ruling on these 10x13 office envelopes These envelopes easily support inter department routing with hole punches for viewing documents without needing to open the envelope Blue Summit Supplies’ 10x13 string envelopes are a go-to solution for anyone seeking reliable document storage or secure mailing options. Crafted from heavyweight 28lb kraft paper, these envelopes are exceptionally durable, resisting tears, punctures, and rips. Their versatile sizing perfectly accommodates letter and legal sized documents without requiring folding or resizing, making them a convenient option for various mailing needs. Whether it's for filing, storing manuscripts, certificates, art prints, posters, or organizing oversized papers without creasing, these envelopes prove to be versatile and reliable in fulfilling multiple office and organizational requirements.