Mayline Kwik-File Mailflow-To-Go Mailroom System Label Holders, 3 x 3/8, Clear, 20/Pack Mayline 90145 Kwik-File Mailflow-To-Go Mailroom System Label Holders, 3 x 3/8, Clear, 20/Pack Keep your mailroom running smoothly. Transparent label holders have self-adhesive backing and fit securely on beveled shelf front. Lets you easily identify contents from above. Includes blank white inserts.