50 Horizontal Mounts, Black, Split-back, Pre-cut, 55 x 36 millimeters (2-3/16 x 1-7/16 inches) - Catalog # MM508 Archival-quality stamp mounts. Mystic mounts are easy to use. Mounts protect your stamps. Mounts make your collection more attractive. Stamps in mounts look great on an album page.