First Day Cover Sleeves – US#6 FDC Mediumweight-Side Open Pack of 50

First Day Cover Sleeves – Safe, archival sleeves are manufactured with the highest standards with rigid polyester and are 100% archival guaranteed for long term storage.  Our completely archival sleeves and holders are Crystal Clear and Fully Transparent on all sides to preserve and maintain the visual quality of your item. SAFE Cover Holders are 100% free of stearates, chemical plasticizers and plasticized PVC for long term storage. 50 Side Opening Sleeves for US No. 6 Size Envelopes or First Day Covers Exterior Size: 6-7/8″ x 4-1/8″H (175 x 105mm) Interior Size: 6-3/4″ x 4″H (open on 4″ side)