Envelopes
Tyvek Mailing Envelope for Storing Lever Arch Files H318xW326xD68mm Ref 990244 [Pack of 50]
Ideal for mailing or storing lever arch files 318x326x68mm Boxed 50
https://www.bizrate.co.uk/envelopes/tyvek-mailing-envelope-for-storing-oid5244046154.html